Pi dee )t 2 

FOTO 

ean ANGIE 
‘ ae 


‘i as 
eye 
( 3 * oe “ 


a 


a 








emer EO ti LTE 
RESEARCH LIBRARY 
Piemarehy RESEARCH INSTITUTE 
JOHN MOORE ANDREAS COLOR CHEMISTRY LIBRARY FOUNDATION 





ter 
= 











A LABORATORY OUTLINE 


OF 


ORGANIC CHEMISTRY 







BY 


LAUDER WILLIAM JONES 


PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF CINCINNATI 








NEW YORK 
THE CENTURY CO. 
1911 










. 


Copyright, 1911, by 










i, aunty ae 


PREFACE. 


TEXT-BOOKS which treat of the experimental aspect of organic 
chemistry are already so abundant that the issuing of a new book 
of this kind would seem to demand some very convincing apology 
on the part of the author. 

The major part of the material included in this book has 
formed the subject matter of a number of distinct courses which 
I conducted in the University of Chicago during the years 1897- 
1907. ‘These courses were planned for large classes, and were 
- arranged to meet the needs of students with diversified interests 
in chemistry. The classes included students in the College of 
Liberal Arts and in the School of Science; premedical students 
and medical students; students somewhat more advanced who 
came for summer courses; and graduate students. Since 1907 
the same outlines have been in use at the University of Cin- 
cinnati, and have been made to include certain phases of the 
subject particularly suited to students of chemical engineering. 

Mimeographed sheets were employed, and were revised each 
year so as to include precautions and changes which actual 
experience in teaching suggested as desirable to make the direc- 
tions as free as possible from the ambiguity so difficult to avoid 
in description of this kind. 

From this brief history it will be apparent that the present 
selection of problems has been determined by the need of meeting 
educational demands both varied and complicated. 

Within the past few years the science of chemistry has pressed 
over its boundaries far into neutral territory, where with other 
sciences, — once almost alien, — it has met for the purpose of 
forming a closer alliance which augurs great mutual benefit to all. 
As a result of this increased cooperation, it has come about that 
students engaged in the study of those sciences which border 
closely upon chemistry, can no longer rest content to follow the 
old-time practice of acquiring a knowledge of chemistry through 

lll 


iv PREFACE 


a brief, and frequently unprofitable period of dabbling in an 
elementary laboratory; or through listening impatiently to a 
few meager lectures designed for a special clan of workers, and 
arranged with the avowed purpose of giving the least possible 
amount of chemistry with the least expenditure of time. 

In most institutions of learning there has grown up an in- 
creasing demand for more intensive as well as extensive training 
in elementary chemistry; and this has brought about corre- 
sponding changes in the curriculum of chemistry. Experimental 
organic chemistry, once a mature part of the course, usually | 
preceded by qualitative and quantitative analysis, and requiring 
a reading knowledge of German and French, now finds itself 
stranded with general inorganic chemistry as its sole prerequisite. 

The majority of laboratory outlines of organic chemistry, 
although for the most part excellent, are designed primarily 
for the mature student in chemistry who is able to read and to 
digest the original articles cited for reference; and for those who 
are concerned more especially with varied manipulation and 
method rather than with a systematic survey of the salient facts 
and relations underlying the science. On the other hand, the few 
briefer and simpler outlines extant can hardly be regarded as 
adequate to give the kind of preparatory training which is now 
being sought in many quarters. 

It would seem, therefore, that there is a place for a text-book 
which shall approach the subject matter of organic chemistry 
in much the same thorough but elementary fashion that we are 
wont to employ in laboratory manuals of inorganic chemistry. 
In other words, there is need of a course in GENERAL ORGANIC 
CHEMISTRY. It is hoped that this book may occupy a position 
and supply a demand of this character. 

From what has been said already concerning the origin of this 
outline, it will be self-evident that it is not intended that any 
one student shall perform all the experiments given on the follow- 
ing pages. On the contrary, it has been my practice to choose 
certain limited sets of experiments to meet the needs of par- 
ticular classes; and, in some cases, to assign different lists of 
experiments to different students of the same class. The re- 
quirements of each case must decide what choice shall be made. 

The experiments have been arranged to follow approximately 
the usual order of subject matter given in most text-books, and 


PREFACE Vv 


in most courses of lectures. However, the sections and chapters 
have been grouped and numbered in such a way that by properly 
chosen assignments other arrangements are easily possible. Thus, 
the aliphatic and aromatic compounds of the same class — e.g., 
hydrocarbons, halogen derivatives, alcohols and phenols — might 
be considered side by side. Similar processes, such as oxidation, 
reduction, esterification, condensation, might be grouped together 
for comparative study. Other similar selections will suggest 
themselves. Many of the experiments have been used for 
lecture demonstration. 

.The questions which are appended to each section are by no 
means intended to exhaust the possibilities in that direction. 
They are merely a few questions which I have found to be valu- 
able in arousing students to assume an inquiring attitude towards 
the work. Explanations of the processes, descriptive matter to 
elucidate reactions, and equations have been omitted advisedly. 
It is to be presumed that upon a shelf in the laboratory there 
will be a number of the best reference works on organic chemistry 
to which the student may be sent for such descriptive matter. 

In conclusion, I wish to acknowledge my indebtedness to the 
many excellent texts on organic chemistry by Emil Fischer, 
Ludwig Gattermann, F. W. Henle, W. A. Noyes, Julius Cohen, 
and others. Very many suggestions have been taken from the 
comprehensive work by 8. P. Mulliken entitled ‘The Identifi- 
cation of Pure Organic Compounds.’ I wish to express my 
obligations to Dr. Martin Fischer, head of the Department of 
Physiology in the University of Cincinnati, for the chapter on col- 
loids. The drawings for the illustrations were made by Mr.. 
Howard A. Dorsey, whom I wish to thank for the personal inter- 
est which he took in making them. There must be other debts 
which I owe and would gladly proclaim at this time; but, at the 
close of the slow process of accretion by which a collection of this 
_ kind is shaped to appear in published form, the various elements 
' become so interwoven that the actual sources of many details 
cease to be clearly defined in the thought of the author. 


LAUDER WILLIAM JONES. 
UNIVERSITY OF CINCINNATI, 
February 21, 1911. 





DIvISsION 
Ir: 


II. 


III. 


IV: 


NV; 
VI. 
VII. 
VIII. 
IX. 


DIvISION 
te 
ai 
XII. 
LIL. 
XIV. 
XV. 
XVI. 
VIE 
XVIII. 


Division 
DeLX. 
XX. 


XXI. 


CONTENTS 


DIRECTIONS FOR THE LABORATORY . . 


PART I. THE ALIPHATIC SERIES. 


1. Tue Monatomic ComMPpounDs 

FRACTIONAL DISTILLATION AND THE Paneae on 
or ABSOLUTE ALCOHOL . 

tee teacne-PAnavrrnn, OunriNs, AND hee 
YLENE .. 

HALOGEN See Swe ere 

Monatomic ALCOHOLS AND ETHERS 

ALDEHYDES AND KETONES . 

Monosasic Farry Acips 

DERIVATIVES OF Farry Acips . 

SULPHUR COMPOUNDS . : 

CoMPouNDS CONTAINING Sean 


C7 6 ue ah oe 


2. PoutyatTomic COMPOUNDS . 
HALOGEN COMPOUNDS . ; 
Potyatomic ALCOHOLS AND Drees 

Disasic AcIDS . 

CYANOGEN AND eee (ore NDE 

UREA AND THE UREIDS i 
PoLtyaToMic COMPOUNDS WITH Mise Eanertone 
CARBOHYDRATES 
Amino AcIDsS . 
CoLLOoIps 


PART II. THE AROMATIC SERIES. 


1. CarsBocyctic CoMPOUNDS 
BENZENE HyDROCARBONS : 
NITROBENZENE AND SOME OF ITs REDUCTION Pear 
UcTS ; 
DIAZONIUM ae AND D1Azo Coane 
DyzEs 


rhsee 


Vii 


PAGE 


89 


95 


Vill 


XXII. 


XXII. 
XXIV. 

XXYV. 
XXVI. 


XXVII. 


XXVIII. 
XXIX. 


CONTENTS 


PHENYLHYDRAZINE. NITROSAMINES. NiITROSO- 
PHENOL. DIPHENYLAMINE Dyess 

PHENOLS AND SOME RELATED COMPOUNDS. 

ALDEHYDES AND KETONES . i: 

Aromatic Acips AND THEIR Duarastoee : 

DERIVATIVES OF DIPHENYLMETHANE AND OF Dt- 
PHENYLETHANE : ; 

DERIVATIVES OF TRiruhyyianeeeee von Tareas 
YLMETHANE Dysgs . 

EXPERIMENTS IN DyYBING q 

NAPHTHALENE AND ANTHRACENE . 


Division 2. HeEtTEROcycLIc CoMPOUNDS 


XXX. 


XXXII. 


HETEROCYCLIC COMPOUNDS: — Murivro Bee eee 
PYRAZOLON; INDIGO; PYRIDINE; QUINOLINE 
METALLO-ORGANIC COMPOUNDS . 


APPENDICES. 


APPENDIX A. TEMPERATURE MEASUREMENT AND HEAT 


Units. Herat VALUE 


APPENDIX B. PrRrEssuRE MEASUREMENT ia 
APPENDIX C. VoLUME AND WEIGHT Re ee SPECIFIC 


GRAVITY 


ApprenpIx D. DIsSsocIATION Conahintaal OF - Onaae Aeues 


AND BASES . 


ApprenpDIx FE. HybDROLYSIS OF Spe OF Winns: Aaa AND 


oF WEAK BASES 


APPENDIX F. Lists or APPARATUS Newoee TO Paepoan THE 


EXPERIMENTS IN THIS OUTLINE 


APPENDIX G. Some SPECIAL APPARATUS FOR Panam 


REAGENTS. 


APPENDIX H. Lists oF Gasss, Tague AND Sousa USED AS 


REAGENTS FOR ORGANIC CHEMISTRY : 


APPENDIX I. ReAGENT BoTTLES AND REAGENT SHELVES . 


134 


137 
142 


143 


149 


155 


156 


159 


164 
173 


DIRECTIONS FOR THE LABORATORY 


General Directions. 

I. Provide yourself with a note-book. A record of each 
experiment and answers to all the questions should be put in 
the note-book. In all equations use the constitutional formule, 
not the empirical formule. An equation, however, will not be 
sufficient; it should be accompanied by a brief account of the 
process, not a mere copy of the directions, but a statement of 
the reasons for the various steps in the operation. If desired, 
a rough sketch of the apparatus may be put in also. 

II. In the case of a few long experiments, two students may 
work together. These experiments are marked “ For two Stu- 
dents.”” In all other preparations, the work must be entirely 
independent. 

III. It is the object of the actual preparation to obtain pure 
compounds. Whenever it is possible, the degree of purity 
should always be ascertained by a determination of the melting- 
point or of the boiling-point of the finished product. 

Concerning Apparatus. 

IV. When the apparatus has been checked, clean it thor- 
oughly before putting it away in the desk. 

V. Prepare a water-bottle for distilled water. 

VI. Cut a glass rod into pieces 6 to 8 inches long, and round 
the rough ends of each piece by heating them in a flame. 

VII. See that you have two pieces of rubber tubing long 
enough to connect the condenser with the water supply. 

VIII. At all times, apparatus not actually in use, which 
tends to accumulate on the top of the desk, should be cleared 
away; a desk with plenty of working space will enable you to 
accomplish more work during a laboratory period. 

Concerning Weights and ‘‘ Yields.’’ 

IX. For all preparations, the prescribed amounts must be 
weighed on an ordinary chemical balance. Do not guess at the 
amounts. 

X. When the yield is called for at the close of an experiment, 
note the amount of pure product, and compare this with the 


2 DIRECTIONS FOR THE LABORATORY 


amount theoretically obtainable. By the amount “ theoreti- 
cally obtainable” is meant the weight of the substance which 
would be obtained if the reaction proceeded completely in one 
direction according to the equation. 

Laboratory Precautions. 

XI. Whenever substances are used which have unpleasant 
odors or evolve injurious gases (e.g., ammonia, bromine, hydro- 
gen sulphide, hydrochloric acid, amyl alcohol, etc.), the opera- 
tion must be conducted under a hood. 

XII. Vessels or apparatus containing volatile materials to 
be heated, or in which gases or vapors are evolved, must not be 
closed air-tight. 

XIII. Inflammable liquids, such as ether, ligroine, benzene, 
etc., in quantities of more than a few cubic centimeters, must 
not be heated over a free flame, but in vessels immersed in 
appropriate baths (water, paraffine, etc.). When such liquids 
are to be removed by distillation, always employ a condenser. 

XIV. Do not put combustible substances in the jars pro- 
vided for solid waste materials. 

Abbreviations. 

XV. The following abbreviations will be used: — 

[R]. = Consult a reference book. 

[Instructions]. = Consult an instructor before you proceed 
with the experiment. 

(?) = An answer must be given before you continue the 
preparation. Record these answers in your note-book. 

{H]. = Hood. 

[S.R.] = Store Room. 

[S.S.] = Side Shelf. 

Ber. = Berichte der deutschen chemischen Gesellschaft. 

Ann. = Liebig’s Annalen. 

Am. Chem. J. = American Chemical Journal. 

J. Am. Chem. Soc. = Journal of the American Chemical 
Society. 


PART I. 
ALIPHATIC SERIES. 


DIVISION 1. MONATOMIC COMPOUNDS. 
DIVISION 2. POLYATOMIC COMPOUNDS. 





OUTLINE OF ORGANIC 
CHEMISTRY 


CHAPTER I. 


FRACTIONAL DISTILLATION AND THE PREPARATION OF ABSOLUTE 


- ALCOHOL. 
Wi e e 

* 1. Fractional Distillation: Separation of a Mixture of 
Ethyl Alcohol and Water. Make a mixture containing 100 c.c. of 
ethyl alcohol (95 per cent.) and 100 c.c. of distilled water. Is there 
any change in temperature when these two liquids are mixed? 


Is the total volume of this mixture exactly 200 c.c.? Measure its 





Fig. 1. 


volume when it has reached the temperature which the water 
and alcohol had before mixing. Will the mixture kindle when 
a flame is applied to it? Pour the dilute alcohol into a 500-c.c. 
flask fitted with a fractionating-column and a thermometer; 
and connect the column with a condenser. 

5 


6 FRACTIONAL DISTILLATION [§ 1 


Heat a piece of glass tubing in the flame of a Bunsen burner. 
When the glass is thoroughly softened, remove it from the 
_ flame and draw it out slowly, to make a narrow tube 1 mm. in 
diameter. Cut this narrow tube into pieces about 5 inches 
long, and seal one end of each piece. Such tubes are called 
“ebullition tubes.”’ They are used to prevent the violent 
“bumping”? which frequently results because of the super- 
heating of liquids. Put one of these tubes, open end down, 
into the flask. : 

To serve as receivers for the distillate, select four clean, dry 
flasks (about 100 c.c.), and number them consecutively from 
1 to 4. Place the distilling-flask over a wire gauze, and apply 
heat sufficient to cause the liquid to distill so rapidly that you 
can still count the drops easily as they fall from the end of the 
condenser. When the flame has been adjusted, see that it 
stands exactly under the center of the flask, but do not alter it 
or remove the burner during the remainder of the distillation. 

Collect successively four fractions which boil between the 
following temperatures: — I, from ¢,°-82° inclusive; II, from 
82+°-89°; III, from 89°-96°; IV, from 96°-4,°. Measure each 
fraction in a graduated cylinder. In more exact separations, 
it is frequently desirable to collect fractions at intervals 
of three to five degrees. This is necessary if the substances 
have boiling-points very close together. As a rule, substances 
whose boiling-points lie far apart are much more easily separated. 
For mixtures which cannot be separated by fractional distilla- 
tion, consult reference books. 

The following scheme will illustrate the method of tabulating 
your results: — 


Fraction I II III IV 
Temperature...... t1°-82° 82°-89° 89°-96° 96°-t2° 
Volumecence see 67 c.c. 45 c.¢c. 25 ¢.¢. 57 ©¢.¢. 


Second Fractionation. To make a further separation, distill 
the four fractions one after the other. However, since no 
one of the fractions has the composition of the original mixtures, 
the liquids will not pass over completely at the previous tem- 








* 
he 
Poe ioe 





A 
emus 
Se. = 








§ 1] FRACTIONAL DISTILLATION 7 


peratures; the alcohol will pass over more rapidly from the 
solutions stronger in alcohol. As a consequence of this altered 
distribution, the two end fractions will grow in volume, while 
the two intermediate fractions will diminish. If this process 
is repeated several times, the intermediate fractions will soon 
become practically negligible. 

To make the second fractionation, clean the distilling flask and 
pour the first fraction (4°-82° inclusive) into it. Make the 
connections previously used, place the flame under the wire 
gauze, and collect the distillate in flask 1. When the tempera- 
ture just exceeds 82°, there will still be some liquid left in the 
distilling-flask. By removing the Bunsen burner, interrupt the 
boiling at this point,.add fraction II (824°-89°), drop in a new 
ebullition tube, and resume the distillation without changing 
the receiving flask. There will be a small amount which will 
distill before the temperature passes 82°. When the tempera- 
ture again exceeds 82°, stop the distillation once more, add 
fraction III (89°-96°), and proceed as before. 

Now add fraction IV (96°-#,°). Even in this case there may 
be a slight amount which will boil below 82°. During the 
treatment of this fraction, when the temperature has reached 
82°, do not discontinue the boiling, but change the receiving 
flask, putting flask 2 in place of flask 1. When the temperature 
has reached 89°, begin to collect the distillate in flask 3; and at 
96°, use flask 4. The following table will show how the re- 
sults should be recorded. 


Fraction I II Ill IV 
Temperature...... t1;°-82° 82°-89° 89°-96° 96°-#,° 
WOHINGs atcisci sl 94 c.c. 10 c.c. 19 c.c. 70 c.e. 


A third fractionation may be made in stages like those just 
described for the second. This will lead to a more thorough 
separation because of the altered composition brought about by 
the second fractionation. Furthermore, it will be evident that 
any single fraction, say fraction I (t°-82°), may be subjected 
to a similar process of fractionation by means of which its sep- 
aration into alcohol and water could be made more nearly com- 


8 FRACTIONAL DISTILLATION [§ 2 


plete.* Try to kindle a sample of fraction I. Does it burn 
now? 

Absolute Ethyl Alcohol. 

2. A Test for Water in Alcohol. Put a little pure-white 
anhydrous copper sulphate in a dry test-tube, and add to it 
5 c.c. of ordinary alcohol. Close the test-tube with a tight- 
fitting stopper, shake it, and allow it to stand for an hour. 
What change in the appearance of the copper sulphate do you 
notice? Explain your observation. 

The Preparation of Absolute Alcohol. Pour 300 c.c. of ordi- 
nary 95 per cent. alcohol into a 1-liter flask. When pieces of good 
quicklime have been added to the alcohol until they reach the 





| Fig. 2. 


surface of it, connect the flask with a reflux-condenser, and heat 
the flask in a water-bath for an hour. During this time the 
alcohol should boil gently. 

When the water-bath has been removed, and the alcohol has 
ceased to boil, take the apparatus apart, and adjust the con- 
denser in the usual position for distillation. A clean, dry filter- 
flask will be found to be the most convenient form of receiver. 
By means of a sound cork stopper, fasten the filter-flask to the 
lower end of the condenser, and connect the side tube of the 
filter-flask with a straight calcium chloride tube, completely 


* A mixture of ethyl alcohol and water containing 95.57 per cent. of 
alcohol has a minimum boiling-point, 78.15° (760 mm.), so that it is 
not possible by distillation alone to make a separation beyond this 
point. Pure alcohol boils at 78.3°. 








§ 2] FRACTIONAL DISTILLATION 9 


filled with porous calcium chloride. [Instructions]. Do not 
close this tube with a stopper. Why? 

After these connections have been made, place the flask once 
more in the water-bath, and apply heat enough to cause the 
alcohol to distill at such a rate that “bumping” is entirely 
avoided. Collect the first 10 c.c. of the distillate in a small 





Fig. 3. 


flask, and allow the remainder to flow into the filter-flask. 
Keep the absolute alcohol in a labeled bottle, well corked; it 
will be needed for later experiments. 

a. Is it possible to prepare alcohol absolutely free from 
water? Apply the test with copper sulphate to the “absolute 
alcohol” which you have just made. 

b. Why do you discard the first portion of the distillate? 
Do the 10 c.c. which you collected first affect anhydrous copper 
sulphate? 

c. Can you suggest any other reagents which might be em- 
ployed to remove water from alcohol? What objections would 
there be to the use of sulphuric acid? of calcium chloride? of 
phosphorus pentoxide? of phosphorus pentachloride? ([R]. 


CHAPTER II. 


THE ALIPHATIC HYDROCARBONS — PARAFFINES, OLEFINES, AND 
ACETYLENES. 


3. Tests for Carbon and Hydrogen in Organic Substances. 
In many cases the presence of carbon in a compound may be 
determined by heating a portion of the substance. If a charring 
occurs, or if gases are evolved which burn with a smoky flame, 
carbon is present. Black oxides or finely divided metals, which 
may be formed by the ignition of certain inorganic salts, must 
not be mistaken for carbon. 

a. Ignite a small quantity of sugar in a porcelain dish. Re- 
peat the experiment, using benzoic acid instead of sugar. 

b. Dry 3 or 4 grams of powdered copper oxide by heating it 
to redness for a few minutes in a small porcelain dish. After 
sealing one end of a glass tube 4-5 inches long, mix a little 
benzoic acid with some dry copper oxide; place the mixture at 
the bottom of the tube, and fill half of the remaining space with 
dry copper oxide. To permit the carbon dioxide and water 
vapor to escape freely, hold the tube in a horizontal position, 
and tap it on the desk so as to form a narrow channel between 
the oxide layer and the upper wall of the tube. First heat the 
upper layer of oxide, and then the lower layer containing ben- 
zoic acid. Prove that carbon dioxide is evolved. Is there any 
evidence of the formation of water? 


A. Sertes of Paraffine Hydrocarbons. 


4. Methane: Its Preparation from Chloroform. Put 10 g. 
of “zinc dust” into a small flask, and cover the powder with 
dilute alcohol (1 part of water to 5 parts of alcohol). Fur- 
nish the flask with a stopper and a delivery-tube, so arranged 
that any gas evolved may be collected in test-tubes over water. 
Then add to the flask about 5 c.c. of chloroform and 1 c.c. of 
copper sulphate solution. The action will commence in the 

10 





le ete Ws Sac oy 

? “Ty - tay, 4 ; * 

ete ee a i see Ee Mig SMI Cs 
eal emer) a Sak bah 








“t 7 oes © 





§ 5] THE ALIPHATIC HYDROCARBONS wa? 


course of a few seconds, and may become too rapid unless the 
flask is cooled slightly from time to time. 

a. Test the inflammability of the gas. What caused the 
slight green mantle of the flame? Would pure methane burn 
with a green flame [R]? 

b. Describe two other methods of preparing methane. 

c. How could you prepare chloroform from methane? What 
name is given to this process? 

d. Define the term “alkyl,” and point out the relation which 
alkyl groups bear to the formule of paraffine hydrocarbons. 

e. How does Kekulé’s hypothesis of the linking of the carbon 
atoms explain the fact that dimethyl and ethyl hydride were 
found to be identical? 


B. Series of Olefine Hydrocarbons. 


~ 6. Preparation of Ethylene from Ethyl Alcohol. Pour 25c.c. 
- of absolute ethyl alcohol into a 1-liter flask, and add 75 c.c. of 
pure concentrated sulphuric acid in small portions, constantly 
shaking the mixture. Should the mixture become decidedly 
warm, cool the flask under the water-tap before you add more 
acid. Why is it dangerous to pour alcohol or water into con- 
centrated sulphuric acid? 

Select a stopper which fits the opening of the flask snugly, 
and bore two holes in it, — one for the thermometer, and one 
for a doubly bent delivery-tube which leads to the first of a 
train of two wash-bottles. Fill each wash-bottle about half- 
full of a concentrated solution of sodium hydroxide. The gas 
should pass from the first wash-bottle to the bottom of the sec- 
ond, and from the second wash-bottle, by means of a long, bent 
delivery-tube, to a pail of water, or a pneumatic trough, where it 
should be collected in bottles over water. See that the bulb of 
the thermometer dips below the surface of the liquid in the flask. 

When you are sure that all connections are tight, heat the 
flask cautiously over a wire gauze, or a sand-bath, until the 
temperature reaches 180°. Regulate the flame so that the tem- 
perature may be maintained as nearly as possible at this 
point, and apply the heat so that a constant stream of gas is 
obtained, without any violent foaming of the reaction mixture. 
When a sample of gas collected in a test-tube over water, 


12 THE ALIPHATIC HYDROCARBONS [§ 6 


burns quietly, fill two 8-ounce tincture bottles and one 8-ounce 
wide-mouthed bottle with the gas. While you take the appa- 
ratus’ ‘apart, notice the odor of the charred product and gases 
in the generator flask. Does this suggest the necessity for 
using pie hydroxide in the wash-bottles? 

a. Pour 1 c.c. of bromine water into one of the tincture 
bottles. Close the bottle with a stopper, and shake it vigor- 
ously. Notice the odor of the colorless liquid. Is there any 
visible evidence of the separation of a new substance? How 
would bromine act upon a solution of sulphurous acid? 

b. Into the second tincture bottle, pour 1 c.c. of a very dilute 
solution of potassium permanganate (just rose color), and add 
1 c.c. of a solution of sodium carbonate. Close the bottle 
and shake it. What change occurs? (This is known as von 
Baeyer’s reaction for the “double bond.’’) 

c. Place a wide-mouthed bottle of the gas on the table, and 
kindle the gas. From the mouthpiece of a water-bottle, imme- 
diately pour a stream of water into the bottle. This will dis- 
place the gas so that a conspicuous flame may be produced. Is 
the flame distinctly luminous? 

d. By means of a rubber tube connected with a gas-cock, fill 
two tincture bottles with illuminating-gas. To the gas apply 
the tests described in a and 6. Can you detect any unsatu- 
rated substance in the gas? What are the chief “ illuminants ”’ 
in coal-gas? 

e. W. ‘hat: would be formed by the action of concentrated 
sulph C acid upon ethylene? Does this product differ from 
the chief compound formed by the action of sulphuric acid 
upon ethyl alcohol at room temperature? How could you con- 
vert ethylene into ethyl alcohol? 

6. Chemical Behavior of Paraffine and Olefine Hydrocar- 
bons Compared. 

a. To 5 c.c. of amylene, gradually add a solution of bromine 
(5 per cent.) in carbon tetrachloride. 

b. Add a few drops of this same bromine solution (5 per cent.) 
to 10 c.c. of dry petroleum ether (ligroine) the boiling-point of 
_ which lies between 40° and 60°. What is the chief constitu- 
ent of petroleum ether of this boiling-point? [R]. Divide the 
mixture into two equal portions, by pouring one half of it into 
a second dry test-tube. Allow one tube to stand in a dark 


=! 











tots 

e 

; 
\ 
2 
*. 
4 
VW 
“I 
be 
~ 
* 
. 
: 

ra) y if ( 
‘ j 

+ .’ 

£ a « 

fy e 

ho ee 

i 
” “ , 

é 
F 








§ 7] THE ALIPHATIC HYDROCARBONS 13 


place in the cupboard of your desk, and expose the other tube 
to direct sunlight. After a few minutes, compare the solutions 
in the tubes. Breathe across the top of the tubes. What 
causes the cloud of vapor? What differences do you observe 
in experiments a and 6? Explain them. 

c. How would ethane and ethylene behave when treated 
with bromine? Is this behavior typical of the two classes of 
hydrocarbons of which ethane and ethylene are representatives? 
By what differences in graphic formule do we picture to our- 
selves this difference in behavior? 

d. By what series of chemical reactions could you convert 
ethane into ethylene, and the reverse? 

e. Upon analysis, a certain hydrocarbon was found to have 
the following percentage composition: — Carbon = 92.37 per 
cent.; hydrogen = 7.63 per cent. What is the simplest empirical 
formula of this hydrocarbon? The vapor-density (air = 1) 
was found to be 0.9. What would be the molecular weight, 
and the formula of this hydrocarbon? 

f. If it were found by experiment that 13 g. of this hydro- 
carbon absorbed 160 g. of bromine, how would you arrive at 
an equation expressing the course of the reaction, and a 
formula for the addition product? 


C. Series of Acetylene Hydrocarbons. 


“ 7. Acetylene: Its Preparation from Calcium Carbide. [H]. 
Fit a clean, dry flask with a stopper having two openings. 
Through one of these openings introduce a dropping-funnel; 
through the other, a tube leading into an empty wash-bottle, 
where it should end just below the stopper. This empty bottle 
serves to prevent water from running back through the delivery- 
tube upon the carbide. When 5 g. of calcium carbide have 
been placed in the flask, permit water to flow, drop by drop, 
upon the carbide. [Caution!] Do not allow a large quantity 
of water to come suddenly into contact with the carbide. 
Do not allow the acetylene to escape any more than is neces- 
sary, for the gas is not only offensive, but also poisonous. As 
soon as a sample of the gas, collected in a test-tube, burns 
quietly when ignited, fill two tincture bottles and one wide- 
mouthed bottle with it. 


14 THE ALIPHATIC HYDROCARBONS [§ 7 


a. Burn the gas contained in the wide-mouthed bottle. 

b. To the second bottle of the gas, add a little bromine water. 
When the color of the bromine is entirely discharged, notice the 
odor of the liquid. Is there any visible evidence of the forma- 
tion of a new compound? How does the behavior of acetylene 
toward bromine compare with that of ethylene and of ethane 
toward the same reagent? [RI]. 

c. Cuprous Chloride and Cuprous Acetylene. Dissolve 5g. 
of cupric oxide in 20 ¢.c. of concentrated hydrochloric acid. 
When the oxide has dissolved, add 5 g. of copper turnings, and 
boil the acid until the green color of the solution changes to 
dark-brown. Pour the solution of the copper salt into a beaker 
containing water. A white precipitate of cuprous chloride will 
be formed; by decantation, this should be separated from the 
acid solution, and dissolved in ammonium chloride and am- 
monia.* 

Pass acetylene into 5 ¢.c. of this solution. What is formed? 
[R]. Collect this precipitate upon a small filter, wash it, and 
dry it. When it is dry, heat a small piece of it in the flame. 

d. Can acetylene be prepared by the direct union of carbon 
and hydrogen? [R]. How could you obtain acetylene from 
ethane, and from ethylene? 


* If desired, the solution of cuprous chloride may be made as fol- 
lows: —To 1 g. of copper sulphate, dissolved in a little water, add 
about 4 c.c. of concentrated ammonium hydroxide solution and 3 g. 
of hydroxylamine hydrochloride. Dilute the solution with water until 
its volume is about 50 ¢c.c. It may be kept colorless by placing it in a 
tightly-corked bottle containing some copper turnings. 





¥ 
Ld 


fi 5 bel : 
VP te 
hams 





CHAPTER III. 
HALOGEN COMPOUNDS. — HALOGEN ALKYLS. 


*8. Tests for the Halogens in Organic Compounds. 

a. To a dilute solution of ethylammonium bromide, add a 
few drops of a solution of silver nitrate. (?) 

b. Add a drop or two of ethyl bromide to a solution of silver 
nitrate. No immediate precipitate is formed. Explain. Allow 
the mixture to stand, and observe what happens. Add asolu- 
tion of silver nitrate to a solution of potassium bromide. What 
difference do you observe in the behavior of ethyl bromide and 
potassium bromide? Which of the two is more like ethyl- 
ammonium bromide in behavior? Explain. 

c. Dissolve 1 g. of potassium hydroxide in 10 c.c. of alcohol. 
By means of nitric acid, acidify 1 ¢.c. of this solution, known as 
“alcoholic potash,” and add a few drops of a solution of silver 
nitrate to it. Is any precipitate formed? What impurities, 
capable of giving a precipitate with a nitric acid solution of 
silver nitrate, are often present in potassium hydroxide? 

d. To 1 c.c. of alcoholic potash, add several drops of ethyl 
bromide, and boil the liquid gently for two minutes. After 
diluting the liquid with water, acidify it with nitric acid, and 
add 3 or 4 drops of a solution of silver nitrate. Compare the 
result with that obtained in 6. 

e. Repeat experiment d, but use a drop of phenyl bromide 
(brom benzene) in place of ethyl bromide. If an oil separates 
when water is added, enough alcohol should be used to dissolve 
this oil completely. Then add not more than three or four 
drops of a solution of silver nitrate. Can bromine in phenyl 
bromide be detected by this process? 

f. Seal a piece of copper wire into the end of a short piece of 
glass rod. Heat the wire in a Bunsen flame until it ceases to 
color the flame; dip it into an organic substance which contains 
a halogen, and heat it again. Test chloroform and phenyl 
bromide in this way. 

15 


16 HALOGEN COMPOUNDS [$ 9 


g. What would be the effect of heating organic compounds 
containing halogens with a mixture of fuming nitric acid and 
silver nitrate in closed vessels at high temperature? How 
would ignition with calcium oxide affect such compounds? 

9. Ethyl Iodide. Place 2 g. of red phosphorus in a small 
flask, and pour upon it 10 c.c. of absolute ethyl alcohol. Add 
17 g. of powdered iodine, a portion at a time. Shake the flask 
after the addition of each portion, and cool it carefully before 
adding the next portion. When the mixture ceases to become 
warm spontaneously, cork the flask, place it in a beaker of cold 
water, and let it stand for 24 hours. Then connect the flask 
with a reflux-condenser, place it in a water-bath, and heat the 
water in the bath until the iodide begins to boil. (Cf. Fig. 2.) 
When the iodide has boiled for 15 minutes, change the position 
of the condenser, and distill the iodide. [R]. At first apply 
a gentle heat; finally, heat the 
bath until the water in it boils 
vigorously. 

When the liquid ceases to 
pass into the receiver, transfer 
the crude product to a small 
separatory-funnel or a dropping- 
funnel. [Instructions]. Wash 
the iodide twice with cold water; 
then, with a dilute solution of so- 
dium hydroxide until the brown 
color, caused by iodine, is en- 
tirelyremoved. Whatimpurities 
are eliminated by these opera- 
tions? After washing the iodide 
once more with water, separate 
it as completely as possible from 
the water, and place it in a dry 
ide flask with solid (not porous) 

Fig. 4. Separatory-Funnel. fused calcium chloride which has 

been broken into pieces about 
as large as grains of wheat. It usually requires several hours 
to dry such preparations completely. Distill it when it is dry. 
A distilling-flask provided with a thermometer should be used 
in this distillation. [R]. Observe the boiling-point, and compare 








° 





§ 10] HALOGEN COMPOUNDS 17 


it with the recorded boiling-point of ethyl iodide. Weigh the 
pure, distilled iodide, and calculate the amount which should 





have been obtained if all of the alcohol had been changed into 
iodide according to the equation. 

a. Is the iodide heavier, or lighter, than water? 

b. When treated with a dilute solution of silver nitrate, does 
ethyl iodide immediately give a decided precipitate of silver 
iodide? 

c. Can you suggest any other ways of preparing ethyl iodide? 
How could you make ethyl bromide? propyl chloride? 

d. What would be formed if ethyl iodide were treated with 

zine dust and dilute alcohol? 
y 10. Action of Light upon Ethyl Iodide. Select three small 
‘ test-tubes of approximately the same size. See that they are 
dry and clean. Put in each tube about 2 c.c. of the freshly 
distilled, colorless iodide. Cork the tubes immediately; and 
place one in direct sunlight, one in diffused light on the desk, 
and the last one in a dark cupboard or drawer. After 15 min- 
utes, compare the samples of iodide in the three tubes. Return 
the tubes to their respective places; and, at the end of the 
laboratory period, compare them again. When the third tube 
has been kept in the dark for several days, observe whether any 
change in the color of the iodide has occurred. 

Why is it customary to preserve iodides in brown bottles? 
How do you explain the fact that metallic mercury will dis- 
charge the brown color which ethyl iodide acquires on exposure 
to light? 


CHAPTER IV. 
MONATOMIC ALCOHOLS AND ETHERS. 


11. Reactions of Alcohols. 

a. After acidifying 1 or 2 ¢.c. of a very dilute solution of 
potassium dichromate with sulphuric acid, add a few drops of 
alcohol, and boil the solution gently. What changes do you 
observe? What causes the odor of the mixture? [R]. What 
class of alcohols will give similar oxidation products? What 
would be formed by the careful oxidation of isopropyl alcohol? 

b. Place 1 or 2 c.c. of ethyl alcohol in a test-tube, and add 
0.5 g. sodium [S.R.] cut into small pieces. [Carz!] What gas 
escapes? When the sodium has disappeared completely, cool 
the solution. What separates? [R]. Try the same experiment 
with methyl alcohol in place of ethyl alcohol. Is the reaction 
which takes place in these two cases a characteristic reaction 
of alcohols? (Cf. glycol, glycerol.) 

c. Mix a few crystals of sodium acetate with a little concen- 
trated sulphuric acid; add a small quantity of ethyl alcohol to 
the mixture, and heat it gently. Pour the product upon a 
watch-glass containing 4 or 5 c.c. of water. Notice the odor of 
the liquid. What is formed? [R]. Try the same test, using 
amyl or butyl alcohol in place of ethyl alcohol. 

d. [H]. To one drop of benzoyl chloride, add three drops of 
a solution of sodium hydroxide and a few drops of ethyl alco- 
hol; warm the solution, and observe the odor of the mixture. 
In a similar manner, treat methyl alcohol with benzoyl chloride. 
This method of making esters is known as Schotten-Baumann’s 
reaction. What is the meaning of the term ester? In what 
Sense are the compounds formed in ¢ and in d to be classed as 
esters? Would you call ethyl iodide an ester? Why do we 
prefer to call compounds of this class esters instead of salts, or 
ethereal salts? 

12. The Methyl Ester of 3,5-Dinitrobenzoic Acid. The 
odor of a compound, even if it be fairly characteristic, can 
rarely be depended upon to identify a compound with a high 

18 


> Sis f 


A . Kh * hy Ait ic 
aes 








§12] MONATOMIC ALCOHOLS AND ETHERS 19 


degree of certainty. As a rule, liquids are not easily purified 
and separated when very small quantities are available. Chem- 
ists, therefore, usually prefer to prepare for identification some 
crystalline derivative of the compound under inspection. A 
solid can generally be purified by recrystallization, and, when 
pure, will have a characteristic melting-point. 

Heat 0.3 g. of 3,5-dinitrobenzoic acid and 0.4 g. of phosphorus 
pentachloride in a very small, dry test-tube, constantly moved 
above a low flame. Finally, boil the mixture gently for a 
minute. Pour the product at once upon a small, dry watch- 
glass. When the acid chloride [R] has solidified, remove the 
phosphorus oxychloride by pressing the crystals upon a piece 
of porous plate. 

Place the dry substance in a small test-tube, add eight or 
ten drops of methyl alcohol, and close the tube with a stopper. 
The reaction will be complete in a few minutes. 

To recrystallize the ester, place it in a small flask (60 c.c.), 
and pour over it about 20 c.c. of dilute ethyl alcohol (3 volumes 
of alcohol and 1 volume of water). Close the flask with a cork 
stopper through which an open glass tube, about a foot and a 
half long, has been inserted. This tube serves as an air con- 
denser to prevent appreciable loss of sol- 
vent. Immerse the flask in a water-bath 
and heat it until the alcohol boils. If the 
ester does not dissolve completely in the 
course of a minute or two, add a little more 
dilute alcohol, and heat the flask again. 
When sufficient alcohol has been used to 
dissolve all of the solid, — except, perhaps, 
a small amount of foreign material, — filter 
the hot solution rapidly through a small 
filter-paper to remove insoluble impurities, 
and cool the filtrate until the ester has sep- 
arated. Collect the crystals upon a Biich- 
ner funnel, and wash them with 4-5 c.c. of 
cold, concentrated alcohol. When the sub- _. Z 
stance is dry, the melting-point should be de- Fig.6. Biichner Fun- 

. > neland Filter-Flask. 
termined. The pure substance melts at 107°. 

Other esters of this acid may be employed to identify the 
corresponding alcohols. They may be prepared according to 





20 MONATOMIC ALCOHOLS AND ETHERS [§ 13 


the directions just given for the methyl ester. They have the 
following melting-points (uncorrected): — Ethyl ester, 92°-93°; 
normal propyl ester, 73°-75°; normal butyl ester, 64°: isobutyl 
ester, 83°-84°. Cf. ‘Appendix A, Table II. 

13. Determination of the Melting-Point. Fill a small 
beaker two-thirds full of glycerol, or concentrated sulphuric acid, 
and place it upon a wire gauze on aring-stand. Passa thermom- 
eter through a small cork, and clamp it by means of this cork 
_ so that the bulb of the thermometer is immersed about mid- 
way in the glycerine. Bend a piece of glass rod of small diam- 
eter so that it forms a stirring-rod triangular at the base, and 
with a handle which reaches to the top of the beaker where it 
is bent at an angle. ~ 

Capillary-tubes for determining melting-points may be made 
best from a test-tube. Heat the test-tube in the blast lamp 
flame until the glass is quite soft; take 
it from the flame, and draw it out 
slowly enough to form a narrow tube 
about 1 mm. in diameter. Pieces 
of this capillary-tube about 3 inches 
long may be closed at one end to 
make the so-called “ melting-point 
tubes.”’ 

A small sample of a dry solid may 
be put into a tube by taking up a 
little of the substance with the open 
end of the tube and tapping the closed 
end upon the desk. If this small 
tube, with the sample in it, is then | 
placed against the thermometer in the 
bath of glycerol, the tube will cling 
to the side of the thermometer, and 
should be adjusted so that the sample 
is opposite the bulb of the thermom- 
eter. Some experimenters prefer to 
fasten the capillary-tubes to the ther- 
mometer. This may be done by means 
of a small rubber ring, made by cut- 
ting a narrow cross section from a piece of ordinary gas-hose. 
Gradually heat the bath of glycerol, and stir it constantly until 











§ 15] MONATOMIC ALCOHOLS AND ETHERS PA 


the sample of solid softens; at this instant, observe the reading 
of the thermometer. Concerning corrections, cf. Appendix A, 
Table IT. 


Note 1.—For a complete account of the various methods em- 
ployed in the determination of melting-points, consult Government 
Bulletin 70, Hygienic Laboratory. A Study of Melting-point 
Determinations. By George Menge. Washington, 1910. 


14. The Iodoform Reaction Applied to Alcohols. Dissolve 
one drop of the compound to be tested (e.g., ethyl alcohol) in 
1 c.c. of water. Place this solution in a small test-tube (8 in.), 
and, for each cubic centimeter of test liquid, add two drops 
of a solution of sodium hydroxide (1:10). Make a solution of 
iodine by triturating in a mortar one part of iodine, five parts 
of potassium iodide, and fifteen parts of water. Drop some of 
this solution slowly into the cold alkaline solution under inspec- 
tion, until the liquid has assumed a pale yellow color. When 
this mixture has stood for two minutes, notice whether any 
iodoform has separated. At room temperature, isopropyl alco- 
hol and acetone give noticeable precipitates; secondary butyl 
alcohol forms a precipitate slowly. 

If no iodoform separates at room temperature, heat the 
solution slowly until a thermometer placed in it indicates a 
temperature of 60°. Maintain this temperature for one min- 
ute. If the color of iodine disappears, add more of the iodine 
solution until the yellow color is permanent. Should no pre- 
cipitate form, set the tube aside for two minutes. Ethyl] alco- 
hol yields an abundant precipitate; while allyl alcohol forms 
only a slight one; propyl, isobutyl, tertiary butyl, and isoamy]l 
alcohol will not give precipitates within the time prescribed. 

15. Tertiary Butyl Alcohol from Acetone. Grignard’s 
Synthesis. Add 4 g. of magnesium turnings to 10 c.c. of dry 
ether, and pour into the mixture 10 c.c. of methyl iodide. Con- 
nect the flask at once with a reflux-condenser, and moderate the 
action by placing the flask in a bath of cold water. When the 
metal has nearly disappeared, cautiously add 12 ¢.¢. of dry ace- 
tone by pouring it in smalt portions through the condenser tube. 

After the reaction is completed, distill the ether. Acidify the 
residue with dilute sulphuric acid, and subject the product to 
distillation. Add solid sodium hydroxide to the distillate, and 


22 MONATOMIC ALCOHOLS AND ETHERS [§ 16 


separate the upper layer of impure tertiary butyl alcohol. After 
this has been dried by means of solid sodium hydroxide, distill it. 
Collect the fraction boiling between 75° and 84°, and freeze it in 
a mixture of ice and salt. The yield is usually 40-50 per cent. 

The boiling-point of pure tertiary butyl alcohol is 82.5°. 
When pure, it melts at 29°. 

16. Diethyl Ether. Caution! Ether is extremely imflam- 
mable. Great care must be taken to keep flames away from any 
apparatus containing it. Provide a flask with a stopper which 
has three openings. Through one of these openings insert a 
thermometer far enough to reach to the bottom of the flask; 
through a second opening, pass a tube bent at the proper angle 
to connect the flask with a condenser; through the third open- 
ing, introduce the dropping-tube, long enough to reach nearly 





to the bottom of the flask. Connect the flask with a condenser 
which dips into a receiver surrounded by ice-cold water. 

Put into the flask a mixture of 75 c.c. of absolute alcohol and 
75 c.c. of pure, concentrated sulphuric acid, and heat the flask 
over a sand-bath until the thermometer indicates a temperature 
of 140°. During the entire operation, the temperature must be 
maintained between 140° and 145°. 

When the temperature has reached this point; and is prac- 
_ tically constant, by means of a cork fasten a dropping-funnel to 
the upper end of the dropping-tube, and fill the funnel with 
alcohol; then allow 100 c¢.c. of alcohol to flow, a drop at a time, 
to the bottom of the flask. Continue the heating for a few 
minutes after all of the alcohol has been added. When this 


a 


as Naar ih) 








§ 16] MONATOMIC ALCOHOLS AND ETHERS 23 


operation is finished, remove the stopper of the flask and notice 
the odor of the vapors which escape. Explain. 

Place the distillate in a separatory-funnel, and wash it sev- 
eral times with small portions of a strong solution of sodium 
chloride to which a little sodium hydroxide has been added. (?) 
Finally, shake it several times with small quantities of cold 
water. What is the specific gravity of ether? [R]. Which layer 
is ether? The purified ether should be separated, dried over 
porous calcium chloride for 24 hours, and distilled. What is 
the boiling-point of pure ether? 

a. Shake 2 ¢.c. of ether with 2 c.c. of water. Add 20 c.c. of 
water, and shake the mixture again. Result? Place 7 c.c. of 
water in a small, narrow test-tube, and mark the height of the 
water by means of a narrow strip of a label. Add 3 e.c. of 
ether, close the tube, and shake the mixture vigorously. When 
the ether has separated, paste another narrow strip of label on 
the tube to mark the line of separation between water and 
ether. Empty this mixture out, and repeat the experiment, 
using 7 c.c. of a saturated solution of salt in place of water. 
Is there any difference in the amount of ether dissolved by 
water and by salt solution? Explain. 

b. What intermediate compounds are formed by the action 
of sulphuric acid upon alcohol? To what class of compounds 
do they belong? 

c. How do you account for the formation of sulphur diox- 
ide and of carbonaceous products in this experiment? What 
would be formed in large quantities if the temperature of the 
experiment were 180° instead of 140°? * 

d. Can you suggest any other methods which might be used 
to prepare diethyl ether? How could you obtain dimethyl ether? 
methyl ethyl ether? 

e. By means of graphic formule, point out the relations 
which diethyl ether and ethyl alcohol bear to water. How 
could you change diethyl ether into ethyl alcohol? 

f. An analysis was made of a compound composed of carbon, 
hydrogen, and oxygen. An interpretation of the quantitative 
results and a molecular weight determination led to the em- 
pirical formula C,Hi0. When this substance was treated with 


* J. U. Nef, J. Am. Chem. Soc. 26, 1549; 30, 645. 


= 


24 MONATOMIC ALCOHOLS AND ETHERS [§ 17 


concentrated hydriodic acid, it gave three compounds: (a) CHslI; 
(b) CsH7I; (c), H:O. When these two iodides (a) and (b) were 
acted on by metallic sodium (Wiirtz reaction), a hydrocarbon was 
formed which was found to have specific properties entirely dif- 
ferent from those possessed by an isomeric hydrocarbon obtained 
by the interaction of metallic sodium and ethyl iodide. What 
is the probable constitutional formula of the first hydrocarbon, 
and of the original compound of the empirical formula C,H 00? 

17. Absolute Ether. After shaking in a separatory-funnel 
500 c.c. of ordinary ether and 10-15 c.c. of water, draw off the 
water, and make the following test with it. 

To a portion, add a little iodine dissolved in a solution of 
potassium iodide. When sodium hydroxide has been added 
until the brown color of the iodine has just disappeared, warm 
the solution gently for a minute or two. Notice the odor of the 
solution and the formation of the slight precipitate. Explain. 

After washing the ether six or eight times with small quan- 
tities of a solution of sodium chloride, transfer the ether to a 
bottle, and add porous calcium chloride to it. Allow the ether 
to remain in contact with the calcium chloride for twenty-four 
hours. Decant the ether into a clean, dry flask, and add 
sodium wire made with a sodium press, or thin pieces of sodium. 
~ Protect the contents of the flask 
by an open calcium chloride tube 
inserted through the stopper. The 
ether should remain over sodium 
until the evolution of the gas, 
which may be quite appreciable 
at first, has ceased entirely. 

Caution! Do not pour water 
into the flask containing the so- 
dium residue. To remove the 
sxe sodium, add alcohol until the me- 

Fig. 9. Sodium Press. tallic particles have entirely disap- 
peared; then add water. 

After placing the ether in a clean, dry flask containing 2-3 g. 
of sodium, it may be distilled and collected in an appropriate 
receiver. (Cf. §2, Absolute Alcohol.) The flask containing the 
ether should be surrounded by water which has been heated to 
50° or 60°; a long condenser should be used. 











CHAPTER V. 


ALDEHYDES AND KETONES. 


Aldehydes. 

18. Oxidation of Methyl Alcohol Catalytically Induced by 
Platinum. Pour 5c.c. of methyl alcohol into a 250-c.c. Soxhlet 
flask. Wrap a fine platinum wire around a glass rod of small 
diameter, so that a spiral about 2 cm. long is formed in the 
middle section of the wire. Fasten one straight end of this 
wire around a short piece of glass rod. The length of this 
straight wire and spiral should be adjusted so that the tip-end 
of the wire barely touches the surface of the alcohol when it is 
lowered into the flask and the rod rests upon the top of the 








E Fig. 10. 
flask. Fold a piece of thin asbestos paper so that it forms a 
trough large enough to cover the mouth of the flask when it 
is placed loosely upon it. 

Heat the platinum wire in a Bunsen flame, lower it quickly 
into the flask, and cover the flask immediately with the asbestos 
roof. The odor of the formaldehyde will become apparent at 
once. If the air supply is properly regulated by adjusting the 
asbestos cover, the platinum wire will continue to glow for quite . 
a while. After some time, if the liquid in the flask is evapo- 
rated, a slight solid residue of paraformaldehyde will remain. 

19. Formaldehyde from Methyl Alcohol. A Test for Small 
Amounts of Methyl Alcohol. Dissolve two drops of methyl 
25 


26 ALDEHYDES AND KETONES [§ 20 


alcohol in 3 c.c. of water contained in a small test-tube. Make 
a compact spiral of fine copper wire by wrapping it about a 
glass rod. The spiral should be about 2 cm. long, and should 
have a straight piece about 20 cm. long. Oxidize the spiral by 
moving it rapidly through a Bunsen flame, and plunge the red- 
hot wire into the alcohol solution; repeat this operation several 
times. 

Pour this liquid into a small test-tube, and add one drop of a 
0.5 per cent. solution of resorcinol. Cautiously pour this mix- 
ture into a second test-tube which contains 4 or 5 c.c. of 
concentrated sulphuric acid. If the second tube is properly 
inclined, the mixture will form a distinct layer upon the sur- 
face of the acid. 

A red zone, slightly violet in color, will appear; and above 
the zone there will be a light flocculent precipitate. This re- 
action is characteristic of formaldehyde; other aldehydes do 
not show this behavior. 

20. Formaldehyde. (For two students.) Place 25 c.c. of 
methyl alcohol in a small distilling-flask, and close the flask 
with a stopper through which an open glass tube passes to the 
bottom of the flask. The side tube of the flask should be con- 
nected with a piece of hard-glass tubing, in which has been 
placed a layer of oxidized copper turnings 2 inches long. To 
oxidize the copper turnings, hold a bundle of them in a pair 
of crucible tongs, and move them for a few seconds to-and-fro 
in the flame of a Bunsen burner. (The turnings are usually 
coated with grease, which should be burned away hefore they 
are used.) Close the other end of the hard-glass tube with a 
stopper and a delivery-tube which leads through a stopper to 
the bottom of an empty 8-ounce bottle surrounded by a mixture 
of ice and salt. Through a second opening in the stopper of the 
bottle, pass a short tube bent at right angle. Be sure that all 
of the connections are tight. How can you test the apparatus 
to determine this? 

When the tube which leads from the bottle has been attached 
to the filter-pump by means of a piece of rubber tubing, heat 
the copper turnings to redness. Place the distilling-flask in a 
bath of water heated to 65° or 70°, and aspirate a slow stream of 
air through the entire apparatus, until the alcohol in the dis- 
tilling-flask has completely volatilized. Be careful not to allow 








§ 21] ALDEHYDES AND KETONES 27 


any condensed alcohol to run down upon the red-hot tube; the 
tube may break if you do. A loose plug of asbestos placed at 





each end of the hard-glass tube may prevent this accident. The 
solution which condenses in the bottle will contain about 40 per 
cent. formaldehyde; some methyl] alcohol and a little formic acid 
will be present. 

a. Filter the liquid. Place most of the solution in an evaporat- 
ing-dish, and evaporate it over a water-bath. What is left? [R]. 

b. Add a little of the formaldehyde solution to an ammoniacal 

solution of silver nitrate, and warm the mixture. To prepare 
ammoniacal silver nitrate, take a few drops of a solution of 
silver nitrate, and add ammonium hydroxide to it drop by drop, 
until the precipitate which forms at first has just dissolved. 
_c. To a dilute solution of formaldehyde, add a few drops of 
a 1 per cent. solution of phloroglucinol; then make the solution 
slightly alkaline by means of sodium hydroxide. No equation 
need be written. 

21. Test for Formaldehyde in Milk. Put 10c.c. of the milk 
to be tested into a casserole or small porcelain dish, and add 
10 c.c. of concentrated hydrochloric acid which contains 1 drop 
of a 5 per cent. solution of ferric chloride. Hold the casserole 
just above a small Bunsen flame, and keep it moving in a rotary 
fashion until the liquid just reaches the boiling-point. Should 
formaldehyde be present, a violet color, more or less pronounced, 
will appear when the temperature reaches 80° or 90°. In the 
absence of formaldehyde, the liquid will assume a turbid yel- 
lowish-brown hue. (Leach’s method.) 


28 ALDEHYDES AND KETONES [§ 22 


This test may be carried out somewhat more simply as fol- 
lows: — Add a few drops of a 5 per cent. solution of ferric chlo- 
ride to some commercial sulphuric acid. Place the milk to be 
tested in a large test-tube, and pour into it rapidly 10 c.c. of 
the prepared acid. If formaldehyde is present, the heat of 
mixing will be sufficient to develop the violet color. (Hehner’s 
method modified.) 

22. Oxidation and Reduction Cell with Formaldehyde and 
Silver Nitrate.* Apparatus:— Two small beakers of about 60 ¢.c. 
capacity; a U tube made by bending the ends of a piece of glass 
tubing about 4 inches long and 8 mm. in diameter, so that 
arms 1 inch long are formed; two electrodes made of platinum- 
foil welded to pieces of platinum wire; a sensitive galvanometer. 

Pour some formalin solution into one beaker, and a solution 
of silver nitrate into the other beaker. Fill the bridge with a 
dilute solution of potassium nitrate, and close the ends by loose 











rolls of filter-paper. The bridge should be completely filled 
with this solution. Place the bridge across the beakers, so 
that the arms dip below the surface of the liquids in the beak- 
ers. Immerse a platinum electrode in each beaker, and con- 
nect the terminals with the galvanometer. A slight deflection 
of the needle will be observed. 


* For an account of the details of this experiment, and a proposed 
ionic mechanism whereby alkalies are thought to increase the reducing 
power of formaldehyde, consult an article by J. Stieglitz, Science, Vol- 
ume 30. 





§ 23] ALDEHYDES AND KETONES 29 


If sodium hydroxide is added to the formalin solution, a 
very appreciable increase in deflection will be produced, showing 
that the reducing effect of the formaldehyde is increased by 
alkalies. On the other hand, the oxidizing effect of the silver 
nitrate solution may be assumed to depend upon the concentra- 
tion of silver ions. If this be correct, any reagent which will 
suppress silver ions should diminish the oxidizing value of this 
solution. This may be shown by adding ammonium hydroxide — 
usually employed in the reduction test of aldehyde — to the silver 
nitrate solution in the beaker; an immediate decrease in the de- 
flection of the needle will be noticed. The formation of complex 
silver-ammonium ions diminishes the concentration of silver ions. 

23. Methylal, Formaldehyde Acetal. Mix 15 g. of para- 
formaldehyde, 50 g. of methyl alcohol, and 1.5 g. of anhydrous 
ferric chloride. Place the mixture in a flask attached to a 





a c 
Fig. 13. a. Linnemann’s Apparatus; 6. Hempel Tube; 
c. Glinsky Tube. 


reflux-condenser, and heat it for 5-6 hours. Subject the reac- 
tion product to distillation, and collect all that passes over 
below 64°. Redistill the liquid, using a fractionating-column, 
and collect the low-boiling fraction separately. If this low- 
boiling portion is placed in a flask connected with a reflux- 
condenser, and is treated with small pieces of metallic sodium, 


30 ALDEHYDES AND KETONES [§ 25 


it will be freed from methyl alcohol, and will boil, for the most 
part, between 41° and 43°. The boiling-point of pure methylal 
is 42°. The yield should be about 90 per cent. 

a. Does methylal have the odor of formaldehyde? 

b. Would you call methylal an ether; if so, to what alcohols 
is it related? 

c. Does methylal reduce an ammoniacal solution of silver 
nitrate? 

24. Action of Concentrated Sulphuric Acid upon Methylal. 
In a small, dry test-tube, treat three drops of methylal with two 
drops of concentrated sulphuric acid. Heat the acid gradually 
until it just begins to show signs of boiling. What is the solid 
white residue deposited upon the cool walls of the tube? Notice 
the odor of the gas. 

25. Acetaldehyde. The Preparation of Aldehyde Ammo- 
nia. (For two students.) If this preparation is commenced, 
it must be carried in one operation as far as the point 
marked ®. It is impossible to interrupt the process at any 
previous point in the experiment. 

Gradually add 75 c.c. of concentrated sulphuric acid to 300 c.c. 
of water. When the mixture is cold, add to it 125 c.c. of alco- 
hol, and cool the solution thoroughly. Put 100 g. of potassium 
dichromate, broken into coarse granules, and 50 c.c. of water 
into a one-liter flask; surround the flask with a freezing-mixture 
of ice and salt. Pour the mixture of alcohol, acid, and water 
into a dropping-funnel, and allow it to flow upon the dichromate 
slowly, and with frequent shaking of the flask. When all the 
alcohol has been added, allow the flask to remain in the freezing- 
mixture for 15 minutes. 

During this interval, select a sound stopper for the flask. 
Pass a safety-tube and an adapter through the stopper, connect 
the adapter with a condenser inclined at an angle of 40°-50°, 
and fill the condenser jacket with water which has a tempera- 
ture of about 30°-40°. To maintain this temperature during 
the latter part of distillation, it will be necessary to run a little 
tap-water into the condenser from time to time. At the upper 
end of the condenser, insert a long tube which leads to a filter- 
flask half filled with ether, and surrounded by a freezing-mixture. 

Before you remove the flask from the freezing-mizture ask for 
instructions. When the freezing-mixture is removed, the con- 








§ 25] ALDEHYDES AND KETONES ol 


tents of the flask may soon begin to boil; and unless the boiling is 
regulated immediately by cooling, the action will quickly become 
so violent that an explosion may result. It is usually necessary 
to warm the flask very gently. But as soon as the first signs 
of boiling are noticed, remove the flame at once, and raise 
the freezing-mixture until it 

touches the lower part of 

the flask. In this way, the 

spontaneous boiling, caused 

by the heat of chemical 
action, may be controlled, 

until the mixture will boil 

quietly of its own accord. 

Finally, apply a small flame, 

which may be raised gradu- 

ally until a large flame can 

be used with safety. When 

the aldehyde has been driven 

into the ether, disconnect 

the flask, and notice the 

odor of the liquid in it. Do you recognize the most pronounced 
odor? How do you account for its presence? 

If, for lack of time, it is impossible to continue the prepara- 
tion, the filter-flask which contains the ether solution of alde- 
hyde may be closed air-tight 
and placed in a cold place un- 
til the next laboratory period. 

®. Surround the filter-flask 
r_ with ice and salt, and satu- 
rate the ether with dry am- 
monia gas obtained from a 
cylinder. [Instructions]. To 
avoid stoppage, pass the am- 
monia into the ether through 
a wide glass tube, best a 
straight calcium chloride tube. 

It will take fifteen or twenty 
minutes for this operation. After the crystals of aldehyde 
ammonia have been collected on a filter, wash them with 
ether, and dry them until all of the ether has completely 








Fig. 15. Vacuum-Desiccator. 


32 ALDEHYDES AND KETONES [§ 26 


evaporated. This may be done conveniently in a vacuum-des- 
iccator. While using ether, be careful to turn out all flames 
on your desk. 

26. The Preparation of Pure Acetaldehyde from Acetalde- 
hyde Ammonia. Mix 10 g. of aldehyde ammonia, entirely free 
from ether, with 15 c.c. of water. Place this solution in a drop- 
ping-funnel, and let it flow, drop by drop, into a distilling-flask 
which contains 20 c.c. of water and 8 c.c. of concentrated sul- 
phuric acid. This mixture should be heated in a bath of boiling 
water while the solution of aldehyde ammonia is dropped into 
it. Pass the aldehyde through a condenser. The end of the 
condenser should reach to the bottom of a small distilling-flask 
which is completely surrounded by a freezing-mixture. [In- 
structions]. Use a few pieces of porous calcium chloride to 
dry the aldehyde; and redistill it without transferring it to 
another flask. After passing the aldehyde through a clean, dry 
condenser, collect it in a second distilling-bulb which is sur- 
rounded with a freezing-mixture. The boiling-point of acetalde- 
hyde is 21°. 

a. Reducing Action of Aldehydes. Clean a test-tube with a 
boiling solution of sodium hydroxide, and place in it 1-2 c.c. of 
Tollen’s reagent. Then add a drop or two of a very dilute 
solution of aldehyde. With proper precautions, one part of 
acetaldehyde may be detected in 250,000 parts of water. Cf. § 22. 


Note 2. — Tollen’s reagent may be prepared as follows: — Make 
a solution containing 0.3 g. of silver nitrate in 3 g. of water; and a 
second solution containing 0.3 g. of sodium hydroxide in 3 g. of 
water. Mix these two solutions, and keep the resulting solution 
in a dark place. It should not be heated. 


b. Add 1 drop of aldehyde to 3 drops of Fehling’s solution, 
and warm the mixture gently. What changes occur? Explain 
them. 


Note 3. — Fehling’s solution can be made by mixing equal vol- 
umes of the following solutions: —A solution of copper sulphate 
containing 34.64 g. in 500 c.c. of water, and a solution containing 
180 g. of Rochelle salt and 70 g. of sodium hydroxide in 500 c.c. of 
water. ‘These two solutions should be mixed just before the reagent 
is used. 








§ 27] ALDEHYDES AND KETONES 33 


c. Polymerization of Aldehydes. By means of a stirring-rod 
moistened with concentrated sulphuric acid, add a trace, not a 
drop, of the acid to a little aldehyde cooled in a freezing-mixture. 
If the aldehyde is thoroughly cooled and stirred with a clean 
stirring-rod, it will finally solidify. Is the odor still like that of 
aldehyde? Explain this change. [RI]. 

d. ‘‘Resin’’ Formation. Warm a few drops of acetaldehyde 
with a concentrated solution of sodium hydroxide. How would 
dilute alkalies act upon acetaldehyde? upon formaldehyde? 
What is meant by the aldol condensation? 

e. Add 1 or 2 drops of acetaldehyde to 10 c.c. of water. To 
1 c.c. of this solution, add 1 c.c. of Schiff’s reagent (rosaniline 
sulphite). Try the action of the same reagent upon a similar 
solution of formaldehyde. 


Note 4. — Schiff’s Reagent may be made by passing sulphur 
dioxide into a solution of 2.2 g. of rosaniline dissolved in 10 c.c. of cold 
water, until the solution is saturated with the gas. Rosaniline hydro- 
chloride or acetate may be substituted for rosaniline itself. Allow 
the solution to stand in a closed flask until it becomes colorless, or 

pale yellow. Then dilute it with 200 c.c. of water, and keep it in 
the dark in a tightly-stoppered bottle. 


.f 27. Chloral and Chloral Hydrate. How could chloral be 
‘ prepared from acetaldehyde? from alcohol? 

Put 10 g. of chloral hydrate in a distilling-flask, and treat 
it with 10 c.c. of pure concentrated sulphuric acid. Distill the 
chloral which results. Use a small iron crucible as an air-bath 
to heat the flask uniformly. Pass the vapors through a con- 
denser, and collect the distillate in a small, dry distilling-flask 
protected by a calcium chloride tube which is attached to the 
side tube. Redistill the chloral, and determine its boiling-point. 

a. Mix the chloral with water in the proportions of one gram- 
molecular weight of chloral to one gram-molecular weight of water. 

b. Dissolve about one gram of chloral hydrate in a little water, 
and add to it a solution of sodium hydroxide. Identify the heavy 

liquid which separates. What does the alkaline solution contain? 
How could you test the accuracy of your conclusions? 

c. By means of the tests which you have just employed to 
characterize aldehydes, can you show that chloral is an alde- 
hyde? 


o4- ALDEHYDES AND KETONES L$ 30 


Ketones. 

98. Acetone. Addition of Acid Sulphites. Mix 10 c.c. of 
acetone with 15 c.c. of a cold saturated solution of sodium hydro- 
gen sulphite. Shake the mixture for several minutes and cool it 
if necessary. What is the crystalline substance? Only ketones 
whose formule contain the group CH;CO will respond to this 
test. Separate the crystals by filtration, and dry them on a 
piece of porous plate. Place this substance in a test-tube to- 
gether with an equal weight of sodium carbonate and 5 c.c. of 
water. Heat the solution and observe the odor. Do aldehydes 
form similar addition products with sodium hydrogen sulphite? 
See acetaldehyde, formaldehyde, benzaldehyde. [RI]. 

29. Condensation. Dibenzylidene Acetone, Dibenzalace- 
tone. Put 5 drops of acetone, | c.c. of water, and 1 ¢.c. of benz- 
aldehyde in a test-tube, and add 5 c.c. of strong alcohol and 
1.5 c.c. of a 10 per cent. solution of sodium hydroxide. After 
mixing these substances, heat the mixture over a flame until it 
has boiled gently for one minute. Cool the liquid, and shake 
it until there is a separation of crystals, which may then be 
collected upon a small filter and washed with 5 c.c. of strong 
aleohol. Recrystallize the product from strong alcohol (5 c.c.); 
collect the crystals on a filter, wash them with 2 c.c. of alcohol, 
and dry them upon a piece of porous plate. The melting- 
point of dibenzylidene acetone is 112°. This test is sometimes 
employed to detect small amounts of acetone (e.g., in urine). 

a. Treat a little benzalacetone with an excess of hydrochloric 
acid. In a similar way try concentrated hydriodic acid.* 

30. Oxidation and Reduction of Acetone. 

a. Does acetone reduce Fehling’s solution or Tollen’s solu- 
tion? Does it color Schiff’s reagent? [RI]. 

b. What would be formed by the reduction of acetone? 
How is acetone prepared from calcium acetate? What would be 
formed if acetone were heated with dilute sulphuric acid and 
potassium permanganate? [R]. What relation doesacetone bear 
to propane? How could it be converted into propane? 

c. Acetone from Isopropyl Alcohol by Oxidation. Dissolve 
0.5 g. of chromic anhydride (CrO;) in 2 c.c. of water, and add 


* Baeyer and Villiger, Ber. 35, 1190 (1902); Thiele and Strauss, Ber. 
36, 2375 (1903). 





§ 31] ALDEHYDES AND KETONES 30 


0.3 c.c. of concentrated sulphuric acid. Put 6 drops of isopropyl 
alcohol in a small distilling-flask (15 ¢.c.), and cautiously add 
0.5 c.c. of the chromic acid solutions to it. Cork the flask imme- 
diately, and incline it so that the side tube dips into a test-tube, 
and just below the surface of a solution containing 0.4 c.c. of 
water, 0.4 c.c. of benzaldehyde, and 2 c.c. of ethyl alcohol. 
Finally, heat the distilling-flask gently for a short time. 

To the distillate collected in the test-tube, add 0.5 c.c. of a 
10 per cent. solution of sodium hydroxide, and boil the mixture 
for about one minute. Recrystallize the dibenzylidene acetone 
from alcohol (1 ¢.c.). Collect the precipitate, dry it, and deter- 
mine its melting-point (cf. § 29). 

sj 31. Acetoxime. Dissolve 10 g. of hydroxylamine in 20 c.c. 

of water, and pour into it a solution of 5.8 g., one equivalent, of 
sodium hydroxide dissolved in 15 c.c. of water. Keep the hy- 
droxylamine solution cold, and shake it while the alkaline solu- 
tion, in small portions, is poured into it. Add 11 c.c. of acetone, 
and allow the mixture to stand for 24 hours. The oxime will 
separate as a white solid. 

Collect the solid upon a Biichner funnel, and wash it once or 
twice with a little cold water. Extract the filtrate with ether, 
using about 20c.c. Pour the ether extract through a dry filter- 
paper, and allow the ether to evaporate spontaneously. The 
total amount of solid obtained should be about 6g. The oxime 
is quite volatile at room temperature, and should be preserved 
in closed vessels. It may be recrystallized from ligroine which 
boils between 40° and 60°. 

a. Carefully dry a small amount of recrystallized oxime in a 
desiccator, and determine its melting-point. Acetone is fre- 
quently identified by converting it into acetoxime. 

b. What would be formed by reducing acetoxime, provided 
metallic sodium and alcohol were used as the reducing agent? 

c. What significance do oximes have for the study of alde- 
hydes and ketones? How could aldehydes and ketones be 
recovered from their respective oximes? 


Note 5.— In this preparation, it is necessary to use sodium hydrox- 
ide and the hydroxylamine salt in equivalent amounts, since acet- 
oxime cannot be extracted from an alkaline solution. (?) In many 
cases in preparing oximes, an excess, even three or four times the 
calculated amount of alkali, is essential. In other cases, however, 


36 ALDEHYDES AND KETONES [§ 32 


an acid solution must be used; e.g., quinone in hydrochloric acid 
gives a dioxime; in alkaline solution, it is reduced. 


\{ 82. Hydrazones. Acetone Phenylhydrazone. Dissolve Ic.c. 

of freshly distilled phenylhydrazine in 0.5 c.c. of glacial acetic 
acid and 10 c.c. of water. Add 0.5 c.c. of acetone to 5 c.c. of 
water, and pour this solution into the phenylhydrazine solution. 
At first, a turbidity will result; and finally, an oil will separate. 
It may be extracted with ether. When the solution has been 
dried and the ether removed, acetone phenylhydrazone will be 
left as an oil. : 

Hydrazones are frequently employed to identify ketones and 
aldehydes. For this purpose, if phenylhydrazine does not yield 
solid crystalline hydrazones, it is the usual practice to choose 
some other hydrazine derivatives which will. Para-nitropheny1- 
hydrazine and para-bromphenylhydrazine have been especially 
useful in this respect. 

33. Acetone Para-nitrophenylhydrazone. Dissolve about 
0.5 g. of para-nitrophenylhydrazine in 5 ¢.c. of glacial acetic acid 
and 10 c.c. of water. Pour this solution into 50 c.c. of water con- 
taining 4 drops of acetone. The mixture will become yellow 
and turbid; and, in the course of thirty minutes, the crystals 
will separate completely. After the para-nitrophenylhydrazone 
has been collected upon a filter and washed, drain it, and re- 
crystallize it from a little hot alcohol. It forms golden-yellow 
crystals which melt at 148°. Because of the slight solubility of 
this hydrazone (.003 g. in 50 c.c. of water), it has been used to 
estimate acetone quantitatively, which can be done by drying 
and weighing the precipitated hydrazone. In this way, the 
distillate obtained from urine acidified with dilute sulphuric 
acid may be tested for acetone. 








CHAPTER VI. 
MONOBASIC FATTY ACIDS. 


) 34. Formic Acid from Oxalic Acid. Heat 40 g. of glycerol in 
an open dish until a thermometer placed in the glycerol indicates 

- a temperature of 175°. When the glycerol has been cooled, pour 
it into a distilling-flask which contains a weight of crystallized 
oxalic acid equal to that of the glycerol. Introduce a thermom- 
eter so that the bulb is surrounded by the glycerol, and distill 
the mixture until the thermometer registers a temperature of 
150°. The distillate is essentially dilute formic acid. At this 
stage, cool the liquid in the distilling-flask to 50°, and add a 
second portion of oxalic acid (30 g.). The mixture may then 
be heated as before. 

Place the combined fractions in a distilling-flask, and subject 
them to fractional distillation. Collect the fraction which boils 
between 105° and 108°. About what percentage of formic acid 
does this liquid contain? [RI]. 

a. Salts of Formic Acid. After a portion of the acid solution 
has been made almost neutral by means of sodium hydroxide, 
evaporate it nearly to dryness, and allow the salt to crystallize. 

b. To prepare the lead and copper salts, heat portions of the 
acid with the respective oxides, and filter the boiling solutions 
through small filter papers. Allow the filtrates to evaporate, 
and examine the salts which remain. Is the lead salt very 
soluble in cold water? . 

c. Reduction. Add a solution of silver nitrate to a little 
of the acid. To neutralize the acid add a slight excess of am- 
monia. Explain the change which takes place when the alkaline 
solution is warmed. 

d. Make a solution of sodium formate, and add a few drops 
of mercuric chloride to it. Warm this solution gently. The 
white precipitate which separates is mercurous chloride, HgCl. 
Collect it upon a filter-paper and moisten it with ammonium 
hydroxide. It will turn black. Is this characteristic of mercur- 

37 


38 MONOBASIC FATTY ACIDS [§ 36 


ous chloride? [R]. The formates are not the only substances 
which reduce mercuric chloride to mercurous chloride. Explain 
the reactions which take place when sodium formate reduces 
mercuric chloride. [R]. Would it be possible to construct an 
oxidation-reduction cell with sodium formate and mercuric 
chloride? Cf. § 22, Formaldehyde. 

e. Decomposition by Sulphuric Acid. Heat a portion of 
the sodium salt with some concentrated sulphuric acid. What 
gas is evolved? Does it burn? 

f. What relation does formic acid bear to formaldehyde? to 
methyl alcohol? to carbonic acid? to methane? How could you 
convert methyl alcohol and formaldehyde into formic acid? 

-g. Could formic acid be prepared by oxidizing methyl alcohol, 
if a mixture of sulphuric acid and potassium permanganate were 
used as the oxidizing agent? Could anhydrous formic acid be 
prepared by distilling a mixture of sodium formate and concen- 
trated sulphuric acid? 

h. What is the best way to prepare the anhydrous acid? [RI]. 
Has formic anhydride ever been obtained? [RI]. 

35. Formic Acid by the Oxidation of Methyl Alcohol. 
Make a mixture containing 30 c.c. of water, 10 ¢.c. of con- 
centrated sulphuric acid, and 12 g. of powdered potassium 
dichromate. Cool the mixture thoroughly, and add 2.5 c.c. of 
methyl alcohol. After a few minutes, heat the mixture on a 
water-bath for fifteen minutes. Distill the product until the 
residue becomes thick. 

Pour most of the distillate into a dish, and neutralize it by 
adding sodium carbonate to it. To make sure that the acid 
shall be in excess, add a few cubic centimeters of the distillate 
which have been kept in reserve for this purpose. Concentrate 
the salt solution until its volume is 10 ¢c.c., and apply the char- 
acteristic tests for formic acid described in the previous prep- 
aration. 

36. Acetic Acid. Place 25 g. of fused sodium acetate in a 
dry distilling-flask, and add to it 15 ¢.c. of pure concentrated 
sulphuric acid. Even if so-called “fused” sodium acetate is 
taken, it must be re-fused just before the experiment. It should 
not be heated much above its melting-point; it will decompose 
and turn dark if this is not guarded against. When the flask 
has been connected with a condenser, heat the mixture of salt 








§ 36] MONOBASICG FATTY ACIDS, 39 


and acid on a sand-bath, and collect the distillate in a small, 
dry distilling-flask. Redistill the acid, and observe the boiling- 
point. 

a. “‘ Glacial Acetic Acid.” Pour a little of the fraction of 
highest boiling-point into a dry test-tube, and surround the tube 
with ice and salt. If the acid does not solidify at once, rub the 
walls of the tube with a stirring-rod. 

b. Salts and their Reactions. Make a strong solution of 
sodium acetate. To one portion of the solution, add a solution 
of ferric chloride, and boil the deep-red liquid; to a second por- 
tion, add a solution of silver nitrate. Results? Does acetic 
acid reduce ammoniacal silver nitrate? 

c. Dissolve a little pure sodium acetate in water and test 
the solution with neutral litmus paper. What is the reaction? 
How do you account for this? Make a concentrated solution 
of neutral soap, and add to it a few drops of phenolphthalein. 
Pour the mixture into a large volume of water. Explain the 
changes observed. 

d. Cacodylic Oxide. [H]. Heat a small crystal of sodium 
acetate with a minute quantity of arsenious oxide. Cacodylic 
oxide is formed. It is extremely poisonous. Be very careful 
when noticing the odor. [RI]. 

e. Is the vapor of acetic acid inflammable? Try to burn it. 

f. What is sugar of lead? How is it prepared? What are 
the commercial sources of acetic acid? 

g. Upon analysis, acetic acid and formaldehyde are found 
to have the same percentage composition: carbon, 39.78 per cent; 
hydrogen, 6.79 per cent.; oxygen, 53.43 per cent. Why do 
chemists assign the formula CH.O to formaldehyde, and the 
formula C,H,O2 to acetic acid? After you have collected the 
actual experimental data [R] by an inspection of the evidence 
for each, state the reasons in logical sequence. 


CHAPTER VII. 
DERIVATIVES OF FATTY ACIDS. 


37. Methyl Ester of Formic Acid. Place 30 g. dry sodium 
formate in a small distilling-flask, and add to it a mixture of 
10 g. of methyl alcohol and 32.5 c.c. pure, concentrated hydro- 
chloric acid (sp. gr. 1.2). To prevent an increase in temperature, 
surround the flask with cold water, and add the acid and alcohol 
slowly. Close the flask air-tight, and allow the mixture to 
stand in a vessel of cold water for 24 hours; then distill the ester 
from a water-bath; and, in a receiver cooled by means of ice, 
collect all that passes over until the vapor reaches a temperature 
of 70°. 

Keep the distillate cold, and add powdered calcium chloride 
to it as long as the solid dissolves. This usually causes the 
formation of two layers of liquid, which may be separated by 
means of a dropping-funnel. The upper layer, which is almost | 
pure formic methyl ester, should be placed in a small flask, 
together with some solid calcium chloride. When the ester is 
dry, pour it into a distilling-flask, and distill it. The boiling- 
point of the ester is 32°. 

a. Is the ester easily soluble in water? 

b. Does it have an acid taste or odor? 

c. What is the empirical formula of formic methyl ester? 
Compare this formula with the empirical formula of acetic acid. 
Compare the boiling-points, solubilities in water, and specific 
gravities [R] of the two compounds. Do they differ in their 
chemical behavior as well as in their physical properties? 

d. How does the behavior of this ester towards sodium hy- 
droxide differ from the behavior of acetic acid towards the same 
substance. [R]. How does this reaction help us in determining 
the constitutional formula to assign to formic methyl ester? 
What are the graphic formule of the two compounds? What 
name do we give to substances which bear this relation to one 
another? How do these formule represent the differences which 

40 


# 





§ 39] DERIVATIVES OF FATTY ACIDS 4] 


have been observed in the chemical behavior of the acid and 
the ester? 

e. What acid bears the same relation to acetic methyl ester 
that acetic acid bears to formic methyl ester? 

~/ 38. Acetic Ethyl Ester, Acetic Ether. In a distilling-flask, 
place a mixture of 20 c.c. of absolute alcohol and 25 c.c. of 
concentrated sulphuric acid. When the flask has been con- 
nected with a condenser, heat it on a wire gauze until a ther- 
mometer which reaches into the liquid indicates a temperature 
of 140°. The temperature must be kept between 140° and 145° 
during the process. Through a dropping-funnel, connected with 
the dropping-tube (cf. § 16, Diethyl Ether) which reaches to the 
bottom of the flask, allow a mixture of 25 c.c. of alcohol and 
25 c.c. of glacial acetic acid to flow into the flask as rapidly as 
the ester distills into the receiver. 

After you have transferred the distillate to a large beaker, 
cautiously add a solution of sodium carbonate, and stir the 
mixture until effervescence almost ceases. Why? Sometimes 
the effervescence is very slight. 

By means of a separatory-funnel, separate the heavy layer 
from the lighter layer of acetic ether. Wash the ester several 
times with small portions of a strong solution of salt. Why? 
Distill the ester after it has been dried by means of porous cal- 
cium chloride. What is the boiling-point? [R]. What yield 
have you obtained? 

‘ 39. Hydrolysis of the Ester. Put in a flask 5 c.c. of acetic 
ethyl ester, 2 g. of solid sodium hydroxide, and 50 c.c. of water. 
Connect the flask with a reflux-condenser and heat the alkaline 
solution for ten minutes. Then distill the solution until one- 
half of the liquid has passed over. What does the distillate 
contain? Empty the remainder of the alkaline solution into a 
porcelain dish, and evaporate it to dryness. What is this 
residue? Show by appropriate tests that your conclusions are 
correct? 

a. Could dilute mineral acids be used to accelerate the hy- 
drolysis of the ester? [RJ]. Are other esters affected in a similar 
manner by dilute acids and alkalies? 

6. What influence would concentrated acetic acid have upon 
the completeness of the hydrolysis of the ester by water? 

c. Compare the method used in the preparation of acetic 


42 DERIVATIVES OF FATTY ACIDS [$ 40 


ethyl ester with that which was used to obtain diethyl ether. 
By equations and words, set forth any analogies which you 
may observe in the two processes, and any similarity in formule 
(type) of the ester and the ether. 

d. Mention two other methods which may be used to prepare 
acetic ethyl ester, and show that these methods also have their 
analogies among the methods used to prepare diethyl ether. 
Are these methods general in their application? 

e. There are two butyric acids which have the same empirical 
formula as acetic ethyl ester (CisH;O.). Write the constitu- 
tional formule of these three substances, and tell how you 
could distinguish and identify each one by properly chosen 
experiments, chemical and physical. Are there any other esters 
of fatty acids which have this same empirical formula (C,H;O;)? 

f. In what respects does the action of sodium hydroxide upon 
acetic ethyl ester resemble the action of sodium hydroxide upon 
the fats and oils? What are soaps? 

40. Acetyl Chloride. Place 25 g. of glacial acetic acid in 
a distilling-flask. A second distilling-flask, which serves as a 
receiver, should be joined to the condenser-tube by means of a 
sound cork. To absorb any hydrochloric acid which may be 
evolved, and at the same time to prevent moist air from enter- 
ing the receiver, connect the side tube of the second distilling- 
flask with a long calcium chloride tube charged with soda-lime. 
Do not pack this tube too tight, and be careful that it does 
not stop up during the distillation. 

By means of a dropping-funnel, allow 20 g. of phosphorus 
trichloride to run into the acetic acid, and at the same time 
prevent the mixture from becoming too warm by surrounding 
the flask with cold water. When all of the trichloride has been 
added, immerse the flask for fifteen minutes in a bath of water 
heated to 40° or 50°; finally heat the water to boiling as long as 
the chloride distills. Redistill it, and observe the boiling-point. 
[R]. The yield varies from 20 to 25 g. 

a. Mix a few drops of the chloride with a few drops of water. 
Care! What gas escapes? What remains in the test-tube? 
How does the action of water upon acetyl chloride resemble the 
action of water upon phosphorus trichloride? 

b. Gradually add 1 c.c. of acetyl chloride to 2 c.c. of absolute 
alcohol. Make the solution slightly alkaline, pour it upon a 








§ 41] DERIVATIVES OF FATTY ACIDS 43 


watch-crystal, and notice the odor. What is formed? In what 
_ respect does this reaction resemble the action of acetyl chloride 


_ upon water? 


41. Acetic Anhydride. When some “fused” sodium acetate 
has been re-fused, grind it to a fine powder, and put 20 g. of it 
into a distilling-flask. A condenser and a receiver similar to 
the ones used in the preparation of acetyl chloride should be 
used in this case also. After surrounding the flask by a bath of 
cold water, place 15 g. of acetyl chloride in a dropping-funnel; 
and, at intervals, allow one-half of this reagent to flow upon the 
acetate. To insure a thorough mixing of the two substances, 
remove the dropping-funnel, and stir the contents of the flask 
by means of a stout glass rod. The remainder of the chloride 
should then be added. 

In order to complete the reaction, attach the flask to a reflux- 
condenser, and heat it in a bath of boiling water for twenty 
minutes. Then arrange the condenser in the position for dis- 
tillation, and heat the flask in an oil-bath. Collect the acetic 
anhydride, and purify it by a second distillation. The boiling- 
point is about 138°. Approximately 20 g. should be obtained. 

a. Mix a few drops of the anhydride with water. Does it 
react with water more readily, or less readily, than acetyl 
chloride? Does the water solution contain any hydrochloric 
acid? How could you detect it? What would its presence 
indicate? How would you treat the anhydride to eliminate 
this impurity? 

b. Treat 1 c.c. of absolute alcohol with 1 c.c. of acetic anhy- 
dride, and warm the mixture gently. Add water to the prod- 
uct, and make it slightly alkaline. Pour it upon a watch- 
crystal, and notice the odor. What is formed? 

c. How is acetic anhydride used to determine the “ presence ’’ 
of hydroxyl groups in organic compounds? to determine the 
“number ’”’ of hydroxyl groups? How may acetyl chloride or 
acetic anhydride be changed into ethyl alcohol? 

d. Is there any method used to prepare ether which is analo- 
gous in principle to the methods which you have just employed © 
in making acetic anhydride? By words and by graphic formu- 
le, point out any similarity in ‘‘type” which you may perceive 
when the formule of diethyl ether, acetic anhydride, and acetic 
ethyl ester are compared. 


CHAPTER VIII. 
SULPHUR COMPOUNDS. 


42. Ethyl Mercaptan. Warm 2 c.c. of a saturated solution 
of potassium ethyl sulphate with 2 c.c. of a solution of potassium 
hydrogen sulphide (33 per cent.). Notice the odor of the mer- 
captan. 

a. When subjected to oxidation, do the sulphur alcohols 
yield aldehydes and ketones? 

b. Do sulphur alcohols give olefines and ethers when they are 
heated with concentrated sulphuric acid? 

c. What is sulphonal? trional? tetronal? How is ethyl mer- 
captan used in their preparation? 

43. Trimethylsulphonium Iodide. Dissolve 3g. of potas- 
sium hydroxide in 30 c.c. of methyl alcohol. Pour the solution 
into a flask (about 200 c.c.), weigh the flask and contents to 
the nearest 0.1 g., and pass hydrogen sulphide into it until 0.8 g. 
has been absorbed. 

Filter this solution into a somewhat smaller flask, connect it 
with a reflux-condenser, and add 5.5 c.c. of methyl iodide by 
pouring it in at the top of the condenser. Keep the mixture 
boiling gently for one-half hour. 

While the solution is still warm, pour it out of the flask, 
leaving the solid potassium iodide behind. Trimethylsulpho- 
nium. iodide will separate when this liquid has become cool. 
Recrystallize the salt from methyl alcohol. 

a. Does a solution of this compound in water give silver 
iodide or silver sulphide when it is treated with a solution of 
silver nitrate? Explain. 

b. How could you prepare the base to which this salt is 
related? Is it an active base? 


44 








CHAPTER IX. 
COMPOUNDS CONTAINING NITROGEN. 


44. Tests for Nitrogen in an Organic Compound. In most 
nitrogenous organic compounds, the nitrogen may be detected 
with the greatest certainty by the formation of sodium or 
potassium cyanide. To complete the test, convert the cyanide 
into Prussian-blue. The test is usually performed as follows: — 

a. In a test-tube, heat to redness a few crystals of acetanilid 
with a small piece of sodium. [S.R.] Cool the fused mass, crush 
the test-tube in a dry mortar, and add 3 c.c. of alcohol. When 
the sodium has entirely dissolved, add water very cautiously. 
Care! Boil the solution and filter it if necessary. After adding 
to the filtrate a drop of a solution of ferrous sulphate and one 
drop of a solution of ferric chloride, warm it gently, and acidify 
it with hydrochloric acid. (To make sure that the solution is 
acid, test it with litmus paper.) If the acid solution is dis- 
tinctly blue, nitrogen is present. If it has a green color, allow 
it to stand for several hours; finally, a slight blue precipitate 
will form. 

b. In a test-tube, heat several crystals of urea with a small 
quantity of soda-lime. What gas is evolved? 

_ Amides. : 

)~ 45. Acetamide. Pour 50 g. of acetic ethyl ester into a flask 
containing 100 c.c. of strong ammonia-water (sp. gr. 0.90). 
When this mixture has become homogeneous, transfer it to a 
distilling-flask, and subject it to distillation. [H]. Put a few 
small pieces of porous plate into the flask to prevent ‘‘bump- 
ing,’ and heat the flask over a wire gauze. Keep the first 
fraction, and test it for alcohol. (?) 

When the temperature indicated by the thermometer is about 
170°, take away the condenser, and put in place of it a long, 
wide glass tube without a jacket; then continue the distillation, 
and collect in a beaker all that passes over between 175° and 
230°. If the amide does not solidify when it has cooled, it will 

45 


46 COMPOUNDS CONTAINING NITROGEN  [§ 46 


crystallize if you rub the walls of the beaker with a stirring- 
rod. To remove the liquid which adheres to the crystals, 
collect them upon a Biichner funnel connected with a filter- 
flask and a pump, and press them upon a piece of porous plate. 
Acetamide boils at 223°. What yield have you obtained? 

a. Recrystallize a small amount of acetamide with chloroform 
as the solvent. Determine the melting-point of the dry crystals. 

b. Heat a few crystals with a strong solution of sodium hy- 
droxide. Notice the odor. What gas is evolved? 

c. Heat a little acetamide with dilute sulphuric acid, and 
observe the odor. What is formed? Explain 6 and c. 

Nitriles. 

“46. Acetonitrile, Methyl Cyanide. Weigh out rapidly 10 
to 15 g. of phosphorus pentoxide, and transfer it to a dry 
retort or to a distilling-flask. This can be done best by 
means of a wide cone made by twisting a smooth piece of 
writing paper. Add 10 g. of acetamide. By means of a thick 
glass rod, carefully mix these two substances thoroughly, 
and cover the mixture with a layer of 10 g. of phosphorus 
pentoxide. 

When a condenser has been connected with the retort, slowly 
heat the retort, either in a bath of Wood’s metal or with lumi- 
nous flame. The heat should be applied in such a manner that 
undue foaming of the mass may be prevented as much as 
possible. Finally, increase the temperature until the nitrile 
slowly distills into the condenser. 

Pour the distillate into one-half its volume of water, and 
shake the mixture. Powdered sodium hydroxide, added to the 
cold solution as long as it will dissolve, will cause the nitrile to 
separate as a lighter layer. It should be removed, dried with 
calcium chloride, and distilled over a little fresh phosphorus 
pentoxide. The boiling-point of acetonitrile is 81.6°. 

a. Does the nitrile affect litmus? 

b. Heat a small quantity of the nitrile with a solution of 
sodium hydroxide. What is the odor? Explain the result. 

c. Could you prepare acetonitrile from ammonium acetate 
without previously isolating acetamide? 

d. How are nitriles used to prepare organic acids? How 
could you pass from acetic acid to propionic acid by a series of 
reactions including this reaction? 








§ 48] COMPOUNDS CONTAINING NITROGEN 47 


e. By what experimental method could you change acetoni- 
trile into acetamide? 

f. Isonitriles: Cf. Amines and Chloroform. 

47. Ester of Nitrous Acid. Ethyl Nitrite. Dissolve 5 c.c. 
of ethyl alcohol and 10 g. of sodium nitrite in 50 c.c. of water. 
Pour this solution into a distilling-flask connected with a con- 
denser and a receiver thoroughly cooled by means of ice. Heat 
the nitrite solution to a temperature of 20°-25°. Make a solu- 
tion containing 50 c.c. of water, 5 c.c. of concentrated sulphuric 
acid, and 5 c.c. of alcohol; pour it into a dropping-funnel, and 
allow it to flow slowly into the nitrite solution. Ethyl nitrite 
will distill. Its boiling-point is 17°. 

a. What product, isomeric with ethyl nitrite, would be formed 
by the action of ethyl iodide upon silver nitrite? How could you 
distinguish them by the difference in their behavior towards 
reducing agents? 

Nitroparaffines. 

48. Nitroethane. What difficulties would you encounter in 
attempting to prepare nitroethane from ethane? Is it possible 
to obtain any nitroparaffines by the action of nitric acid on 
paraffine hydrocarbons? 

The Sodium Salt of Nitroethane. Dissolve 0.5 g. of 
nitroethane in a little alcohol, and add to it a solution of sodium 
ethylate, made by allowing 0.2 g. of sodium to act upon a 
few cubic centimeters of ethyl alcohol. After transferring the 
precipitate to a filter, wash it with a little cold alcohol, and 
finally, with ether. When the salt has been dried, make the 
following tests: — 

a. Heat a small piece of it on a spatula. 

b. Dissolve some of the salt in the water. To one portion of 
the solution, add a solution of mercuric chloride; to a second 
portion, add bromine water. 

c. Dissolve about one-half of the remaining salt in water, 
and add dilute sulphuric acid to it. What gas is evolved? 
Warm the solution, and observe the odor of the vapor which 
escapes. (?) 

d. Ethyl Nitrolic Acid. Dissolve the remainder of the salt 
in water, and add to the solution a few crystals of sodium nitrite; 
acidify the solution slowly by adding dilute sulphuric acid; 
then add sodium hydroxide to it until it reacts alkaline. What 


oi 
? 
7 


48 COMPOUNDS CONTAINING NITROGEN [§ 51 


causes the solution to assume a red color? How could you 
isolate ethyl nitrolic acid? Is it a colored substance? 

49. Pseudonitroles. Mix a little silver nitrite with an equal 
volume of dry sand, and transfer it to a small distilling-flask 
(15 c.c.) with a side tube about 20 cm. long. Pour 8-10 drops 
of isopropyl iodide upon the nitrite, and close the flask at once. 
When the sudden evolution of heat has moderated, distill the 
product over a small flame. No condenser need be used. Col- 
lect the distillate in a long test-tube, and shake it with 
three times its volume of a solution containing potassium nitrite 
and a little potassium hydroxide. Add dilute sulphuric acid, 
a drop at a time, until the solution reacts acid. Make it alka- 
line once more, and acidify it again. The blue color is caused 
by a pseudonitrole, which may be extracted by chloroform. 

a. Cf. §48, c, Nitroparaffines. Is the difference in behavior 
towards nitrous acid observed in these two cases characteristic 
of primary and secondary nitroparaffines in general? 

50. Brom-nitrosopropane. To a dilute solution of acetone, 
add a few drops of a 10 per cent. solution of hydroxylamine 
hydrochloride and 1-2 drops of pyridine. Pour upon this solution 
about 1 c.c. of ether, and add bromine water gradually until the 
ether assumes a yellow color. When a few drops of a solution 
of hydrogen peroxide are added, and the mixture is shaken, the 
ether will assume a blue color. The color is caused by brom- 
nitrosopropane. (This reaction is employed to detect small 
quantities of acetone. Sensitiveness: 1 mg. in 5 ¢.c.) 


The following equation expresses the course of the reaction. Ace- 
toxime, which is first formed, reacts with bromine. 


CHs. CH: . 
C = NOH+ Br.— C = NOBr + HBr. 
CH; ” CH; % 


Pyridine accelerates the rearrangement of the compound. 


CH; te C= NOR Neo as Br 
CH, ” CH; NO 


Hydrogen peroxide disposes of impurities. (Piloty, Ber. 35, 3099.) 





Amines. 
61. Methylamine from Acetamide. (For two students.) 
Bromine must be handled with great care. Conduct the work 








§ 51] COMPOUNDS CONTAINING NITROGEN 49 


under a hood, and be careful not to breathe the bromine vapors or 
to spill any of the bromine on your hands. [Instructions!] Grad- 
ually add a cold solution of potassium hydroxide (25 g. of KOH 
in 100 c.c. water) to a mixture of 20 g. acetamide and 18 c.c. bro- 
mine (not bromine water). Keep this mixture cold while the 
potassium hydroxide is added, and stir it to prevent local heat- 
ing. If a precipitate separates at this point, add a little water 
to dissolve it, and proceed. When the mixture assumes a pale- 
yellow color, place it in a dropping-funnel, and allow it to flow in 
a slow stream into a flask containing 60 g. of potassium hydroxide 
dissolved in 180 c.c. of water. The temperature of the alkaline 
solution in the flask should be kept between 60° and 70°; it should 
not rise above 75°. Since considerable heat is evolved during 
the mixing of the solutions, it will be necessary to prevent over- 
heating, by cooling the flask from time to time. During this part 
of the operation, and throughout the preparation, the flask should 
be connected with a condenser. The lower end of the con- 
denser-tube should project into a receiver which contains a little 
ice-cold water, and should dip just below the surface of the water. 

When the mixture has been kept at this temperature until the 
solution in the flask is practically colorless, the amine may be 
distilled. Put afew small pieces of clay-plate in the flask, place it 
upon a wire gauze, and, at first, heat it very gently with a small 
flame to prevent a sudden evolution of methyl amine gas, which, 
by its pressure, may burst the flask. The heat must be in- 
creased very gradually. Finally, boil the solution for several 
minutes until all of the amine has passed through the condenser. 

a. Observe the odor of the solution collected in the receiver. 
Is it exactly like that of ammonia? 

b. Does the solution have an alkaline reaction towards 
methyl-orange? towards litmus? For this test, make the 
methyl-orange and the litmus solutions slightly pink with acid, 
and divide each solution into two parts. To one part of each, 
add some of the amine solution; to the second part, add am- 
monium hydroxide solution. What do you conclude from the 
similarity in behavior? 

c. Add some of the amine solution to a drop of copper sulphate 
solution, then, to a drop of aluminum sulphate solution. Repeat 
these tests, using ammonium hydroxide in place of the amine. Is 
there any similarity in behavior? Explain these reactions. 


90 COMPOUNDS CONTAINING NITROGEN [§ 53 


52. Methylammonium Chloride. After making these tests 
with the water solution, add dilute, pure hydrochloric acid to 
the cold amine solution until the liquid has a slight acid reaction. 
When the hydrochloric acid solution has been evaporated to 
dryness on a water-bath, the dry crystalline residue should be 
dissolved in the least possible amount of boiling absolute alco- 
hol. In this process, use a small flask attached to an air con- 
denser. A very small residue of ammonium chloride may remain 
undissolved at this point. If there should be a slight, insoluble 
residue, filter the solution, and evaporate the filtrate to dryness 
over a water-bath. 

a. Heat a small amount of the solid hydrochloride with a 
solution of sodium hydroxide. Notice the odor. What gas 
escapes? 

6b. Warm some of the salt with calcium oxide in a small, dry 
test-tube. Is the gas which escapes inflammable? Test the 
vapor with litmus paper. 

c. Try the same tests with ammonium chloride in place of 
methylammonium chloride. Write all equations necessary to 
emphasize the similarity in the two cases. 

d. Chlorplatinate. Dissolve some of the salt in a little alco- 
hol, and add to it a few drops of a 10 per cent. solution of platinic 
chloride. If no precipitate appears, add a few drops of ether 
to this solution. “What isformed? [R]. To one drop of a solu- 
tion of ammonium chloride, add a drop of platinic chloride 
solution. Compare the precipitates formed in the two cases. 

e. Isocyanide Reaction for Primary Amines. [H]. Place a 
few crystals of the hydrochloride in a test-tube with two or three 
drops of chloroform; add 1 or 2 c.c. of a solution of potassium 
hydroxide in alcohol, and warm the mixture under the hood. 
The isocyanide can be recognized in small amounts by its odor. 
It is poisonous. When you have finished the test, pour the 
contents of the test-tube into the hood-sink, and rinse out the 
tube with concentrated hydrochloric acid before you take it 
to your desk. Is it possible to prepare a salt of hydrogen isocy- 
anide by heating ammonia with alcohol potash and chloro- 
form? [RI]. , 

53. Triethylammonium Bromide from Diethylamine. In 
a small flask, mix 5 g. of diethylamine and 8 g. of ethyl bromide. 
Allow the mixture to stand one day. Connect the flask with a 








§ 55] COMPOUNDS CONTAINING NITROGEN ol 


reflux-condenser, and heat it for a few minutes upon a water- 
bath. Cool the reaction product,.collect the crystals upon a 
filter, and dry them carefully. 

a. With this salt in place of methylammonium chloride, try 
the test described under § 52, a-e. 

54. Triethylamine. Place the triethylammonium bromide 
in a small, dry distilling-flask connected with a condenser, and 
add to it 4 g. of powdered potassium hydroxide. Heat the 
flask in a bath of boiling water, and collect the amine in a cool 
receiver. Determine the boiling-point of the amine. 

a. Dissolve a few drops of triethylamine in water and apply 
the tests described under § 51 a-c. 

55. Tetraethylammonium Bromide. Weigh the triethyl- 
amine just obtained and mix it with the calculated amount 
(one gram equivalent) of ethyl bromide. In the course of a 
day, long needles of tetraethylammonium bromide will separate. 

a. What is the base to which this salt is related? How would 
you prepare it from the bromide? Is it an active base? [Rl]. 











DIVISION 2. POLYATOMIC COMPOUNDS. 





A eed - 
ohh 
» Le a 
. ee eth . 
* x 











CHAPTER X. 
HALOGEN COMPOUNDS. 


56. Ethylene Dibromides. Pour a mixture of 25 g. of abso- 
lute alcohol and 150 g. of pure concentrated sulphuric acid into 
a 2-liter flask. Support the flask over a wire gauze, and close 
it with a stopper having two openings. Through one opening, 
insert a long-stemmed dropping-funnel; through the other, a 
doubly-bent delivery-tube leading to the first of a train of three 
wash-bottles. Charge the first wash-bottle with concentrated 
sulphuric acid; the second with a strong solution of sodium hy- 
droxide. The third wash-bottle should contain 40 g. of bromine, 
covered with a layer of water, and should be placed in a vessel 
of cold water. 

Heat the flask cautiously until a regular evolution of gas 
begins; then, through the dropping-funnel, introduce a mixture 
of one part of alcohol and two parts of concentrated sulphuric 
acid. This mixture should be added fast enough to furnish a 
constant stream of gas; at the same time, violent foaming of the 
charge should be avoided. When the bromine has changed 
completely into a transparent, almost colorless liquid, transfer 
the contents of the absorption bottle to a separatory-funnel, and 
wash the heavy oil first with a dilute solution of sodium hy- 
droxide, and then with water. Why? Separate the oil, and 
dry it with calcium chloride for several hours. Distill it, and 
preserve it for the preparation of glycol. (Cf. § 59.) 


Note 6.— A mixture of 50 c.c. of phosphoric acid (sp. gr. 1.7) and 
25 c.c. of alcohol may be substituted for the sulphuric acid and 
alcohol. If alcohol is run into this mixture, heated to about 200°, 
a constant stream of ethylene will be obtained without the foaming 
so objectionable when sulphuric acid is employed. 


~~ 57. Chloroform. Select a 2-liter flask and fit it with a 
stopper which has two openings. Through one of the openings 
insert a bent tube which serves to connect the flask with a con- 

55 


56 POLYATOMIC COMPOUNDS [§ 57 


denser; through the second, introduce a tube long enough to 
reach to the bottom of the flask, and arranged so that steam may 
be conducted through it. The tube which reaches to the bottom 
of the flask must be wide in order to avoid stoppage; a straight 
calcium chloride tube, or a dropping-tube, will answer. 

To generate a current of steam, use a 1-liter flask * with a 
stopper which has two openings, one for an exit tube, and the 
other for a glass tube, two or three feet long, which serves as a 
safety-valve. Place the contents of two half-pound boxes of 
bleaching-powder and 700 c.c. of water in the 2-liter flask. 
Slowly add a mixture of 25 c.c. of acetone and 50 ¢.c. of water; 
shake the flask frequently during the addition, and cool it at 
once if the mixture becomes decidedly warm. Finally, support 
the flask upon a tripod covered by a piece of wire gauze, and 






Fig. 16. Steam Distillation. 


connect it on the one side with the condenser and on the other 
side with the steam generator. 

When these connections have been’made, heat the contents 
of the 2-liter flask until the liquid in it is near the boiling- 
point, pass a rapid current of steam into the flask, and drive’ 
the chloroform into the condenser. Collect all of the dis- 
tillate until you can see no more globules of oil in the liquid as it 
drops from the end of the condenser. 

To purify the chloroform, shake it several times in a separa- 
tory-funnel with a saturated solution of salt. Why? Dry it 


* A tin ether can may be used in place of a glass flask. 








§ 58] POLYATOMIC COMPOUNDS o7 


with fused calcium chloride, and distill it. At what temperature. 
does pure chloroform boil? [R]. What yield of chloroform have 
you obtained? 

a. Try to burn a little of the chloroform. 

6. Warm two or three drops of chloroform with a crystal of 
potassium dichromate and a small amount of concentrated 
sulphuric acid. Observe the odor of the vapors which escape. 
What changes take place in moist chloroform when it is exposed 
to air and light? [RI]. 

c. Isonitrile Reaction. [H]. Warm one drop of water solu- 
tion of aniline with a drop of chloroform and a little alcoholic 
potash. Perform the experiment under the hood; empty the 
liquid into the sink under the hood, and wash the test-tube 
with concentrated hydrochloric acid before you take it to your 
desk. To what class of amines does aniline belong? Cf. § 51, 
Methylamine. 

d. What substances would be produced by sean chloroform 
with alcoholic potash? 

e. Add a small crystal of iodine to some Biloretcrn 

f. What methods are employed to prepare pure chloroform 
for use as an anesthetic? 

_j 68. Iodoform. Put into a small flask 10 g. of anhydrous 
sodium carbonate, and dissolve it in 60 c.c. of warm water. 
Add 8 e.c. of alcohol to this solution, immerse the flask in a 
water-bath, and heat the liquid to a temperature between 70° 
and 80°; then add gradually 6 g. of powdered iodine. If the 
solution has a brown color when it has been heated for a few 
minutes, add a solution of sodium carbonate, drop by drop, until 
the brown color just disappears. Cool the liquid, collect the 
iodoform upon a small filter, and wash it with water. When 
the solid has drained, recrystallize it from alcohol as follows. 

After sufficient alcohol has been used to dissolve all of the 
yellow precipitate, filter the hot solution rapidly through a 
small paper, which will remove insoluble impurities, chiefly 
unchanged sodium carbonate; and add water to the filtrate until 
the iodoform is completely precipitated as a yellow crystalline 
deposit. Cool the mixture, and collect the precipitate upon a 
small filter. When the recrystallized iodoform has been dried, 
preferably upon a small piece of porous plate, determine its 
melting-point. 


CHAPTER XI. 
POLYATOMIC ALCOHOLS AND DIKETONES. 


59. Ethylene Glycol. In a flask connected with a reflux- 
condenser, heat 40 g. of ethylene dibromide with 28 g. of an- 
hydrous potassium carbonate and 250 c.c. of water, until the 
ethylene dibromide has disappeared. This operation will require 
some 10-12 hours. To prevent “bumping,” place in the flask 
several long pine splinters. When the oily dibromide has dis- 
appeared, remove the water by evaporation. Owing to the 
volatility of the glycol with 
steam, there will be less loss 
of glycol if the solution is 
concentrated under diminished 
pressure. 

Two distilling-flasks should 
be connected air-tight by means 
of rubber stoppers. Through 
the stopper of the distilling- 
flask proper, insert a glass 
tube drawn out to a wide 
capillary. The tip of this cap- 
illary must nearly touch the 
: , bottom of the flask; and at all 

Fig. 17. Distillation in vacuo. times during the distillation, it 

should dip below the surface of 
the liquid. A piece of rubber tubing and a screw-clamp at- 
tached to the upper end of the glass tube will make it possible 
to regulate the amount of air admitted. The constant forma- 
tion of air bubbles at the lower end of the capillary will pre- 
vent the “bumping” of the boiling liquid. When it is desirable 
to know the temperature at which a given substance is distill- 
ing, a thermometer may be placed inside this glass tube with 
its bulb resting on the shoulders where the capillary begins, and 
with its upper end just below the clamp, so that by removing 

08 











- 


§ 60] POLYATOMIC ALCOHOLS 59 


the clamp and the rubber tube, the thermometer may be taken 
out easily. 

The flask which serves as a receiver, may be cooled if desired. 
In some cases it is necessary to insert a short condenser be- 
tween the two flasks to insure sufficient cooling. A filter-pump 
will give the desired diminution of pressure. When the pressure 
under which a substance is distilling is to be determined, a 
manometer (cf. illustration) should be inserted between the re- 
ceiving flask and the pump.* In the preparation of glycol, 
since only the solvent is distilling, no thermometer or manom- 
eter will be needed. 

When most of the water has distilled and a considerable 
amount of salt has separated, treat the residue with alcohol to 
extract the glycol from the crystals of potassium bromide. When 
the alcohol has been removed by distillation in vacuo, distill 
the residual glycol at atmospheric pressure. The fraction which 
boils between 170°-200° will be practically pure glycol. About 
4-5 g. will be obtained. The boiling-point of pure glycol is 197.5°. 

a. ‘What would the theoretical amount of glycol be? How . 
do you account for this loss? Are any other products formed? 
What would be the chief product if ethylene dibromide were 
heated with alcoholic potash? How could you verify your 
conclusions experimentally? Try your method. 

b. Treat a little glycol with a piece of metallic sodium. Ex- 
plain your result. 

c. Taste a drop of glycol. 

d. Glycol is a diprimary alcohol. What are its oxidation 
products? 

e. What is ethylene oxide? Would you call it an ether? Is 
the method by which ethylene oxide is usually made similar to 
any method used to prepare dimethyl ether? 

60. The Glycol Ester of Benzoic Acid. In a test-tube, mix 
2 drops of glycol, 0.2 c.c. of benzoyl chloride, and 5 c.c. of a 
10 per cent. solution of sodium hydroxide. Close the test-tube 
and shake it for several minutes. After adding 10 c.c. of water, 
shake the tube again, and collect the precipitate upon a filter. 
Wash this precipitate, dissolve it in about 25 c.c. of dilute alco- 
hol (1: 1), and filter the hot solution to remove any suspended 


* Concerning special forms of apparatus used in fractional distillation 
under diminished pressure, consult reference books. 


60 POLYATOMIG ALCOHOLS [§ 61 


particles. Collect the precipitate which forms in the cold solu- 
tion, wash it with 5 c.c. of dilute alcohol (1:1), dry it, and 
determine its melting-point. It should melt at 70°-71°. Cf. 

§§ 11, 12, 40 6, Schotten-Baumann’s reaction. 

‘\ 61. Glycerol. 

a. Add two or three drops of a dilute solution of copper 
sulphate to a solution of glycerol. Make this solution slightly 
alkaline by adding a solution of sodium hydroxide. Does a 
precipitate form? How do you explain the sudden change in 
color? Add a solution of sodium hydroxide to a dilute solution 
of copper sulphate containing no glycerol. What difference do 
you observe? 

b. Glycerol Ester of Benzoic Acid. Dissolve 4 drops of gly- 
cerol in 10 c.c. of a 10 per cent. solution of sodium hydroxide 
contained in a small flask, and add 1 c.c. of benzoyl chloride. 
Close the flask, and shake it vigorously for several minutes, 
until a curdy precipitate has formed. It may be necessary to 
cool the flask from time to time. Add 10 c.c. of water and shake 
the flask again for a few seconds. Collect the precipitate upon 
a filter, wash it with water, and then with 10 c.c. of dilute 
acetic acid? Why? 

Finally, dissolve it in 15 ¢.c. of boiling alcohol (2 parts alcohol 
to 1 part water), filter the solution, cool the filtrate, and shake 
it until the ester is precipitated. Collect the precipitate upon 
a filter, wash it with 8 c.c. of dilute alcohol (2: 1), dry it, and 
determine the melting-point. The pure ester melts at 70°-72°. 
Cf. § 11, Ethyl Alcohol; § 60, Glycol Ester. 

c. What are the chief constituents of the fats? In what re- 
spects are they related chemically to the ester of benzoic acid 
made in b? How is glycerol obtained from the fats? What 
is lipase, and how does it act in decomposing and in synthe- 
sizing fats? 

d. How is ‘“‘notroglycerine” made? Why is the name “‘nitro- 
glycerine” chemically a misnomer? 

e. Acrolein from Glycerol.* Put 1g. of glycerol and 0.1 g. 
of phosphoric acid (sp. gr. 1.7) in a dry test-tube. Close the tube 


* Note 7.— Powdered fused potassium acid sulphate may be substituted 
for phosphoric acid; it is objectionable because of the violent foaming 
of the mixture which it causes. The method given above was proposed 
by Nef, Ann. 335, 221 (note). 








§ 63] POLYATOMIG ALCOHOLS 61 


with a stopper which has a bent delivery tube some 20 cm. long. 
The end of this tube should dip beneath the surface of 2 c.c. of 
water in a small test-tube. Heat the glycerol for a few minutes 
at a temperature of about 240°. Filter the water solution, and 
apply the following reagents: — Fehling’s solution; ammoniacal 
silver nitrate; Schiff’s reagent. 

_ a-Diketone Derivatives. 

62. Nickel Salt of Dimethylglyoxime. Put one drop of a 
solution of nickel nitrate or chloride (10 per cent.) in a large 
test-tube; fill the tube with distilled water, and mix the liquids 
thoroughly. Pour one drop of this solution upon a few crystals 
of dimethylglyoxime, and make this mixture faintly alkaline by 
adding a little very dilute ammonium hydroxide. The red 
substance which forms is a nickel salt of dimethylglyoxime, 
CsHisN.O,Ni. This reaction furnishes a most delicate test for 
the presence of a nickel salt. It may be used to detect nickel 
in the presence of a large amount of cobalt; e.g., in commercial 
cobalt salts. 

6-Diketones. 

63. Acetylacetone. 

a. To a dilute solution of acetylacetone in water, add a drop 
or two of a dilute solution of ferric chloride. Explain the 
change which occurs. 

b. To a solution containing 1 g. of copper acetate in 25 c.c. 
of water, add 0.5 g. of acetylacetone. A blue copper salt of 
acetylacetone, almost insoluble in water, will separate readily. 
When the mixture has been shaken until there is no further in- 
crease in the volume of precipitate, collect the copper salt upon 
a filter, wash it with water, and dry it. Dissolve the dry salt 
in some boiling chloroform. Add hot alcohol until a precipi- 
tate commences to form and allow the salt to crystallize slowly 
from this solvent. Collect the crystals, wash them with alcohol, 
and dry them. The melting-point is 230°. 

c. Heat some dry crystals of the copper salt in a dry test- 
tube. If heat is applied gently, a green vapor will form, and 
the salt will sublime and deposit in bright blue needles. If the 
heat is too great, copper will be deposited. 


CHAPTER XII. 
DIBASIC ACIDS. 


64, Oxalic Acid. Heat 1g. of dry sodium formate in a small 
test-tube. When the salt melts, does it boil, or is a gas evolved 
as a result of decomposition? Apply a flame to the mouth of 
the test-tube. Cool the fused mass, dissolve it in water, and 
add a few drops of a solution of calcium chloride and a little 
acetic acid. (?) Dissolve some unchanged sodium formate in 
water, and treat the solution with calcium chloride and acetic 
acid. Does a precipitate form in this case also? Explain your 
observations. 

a. Calcium Salt. Neutralize a solution of oxalic acid by 
means of ammonium hydroxide. Add a solution of calcium 
chloride. Is the precipitate soluble in acetic acid? What use 
is made of this salt in detecting small amounts of calcium, and 
in estimating calcium quantitatively? What other salts of cal- 
cium are soluble with difficulty in acetic acid? 

b. Heat a few crystals of oxalic acid, or an oxalate, with some 
concentrated sulphuric acid. What change occurs? What gases 
are evolved? Make appropriate tests for each gas. 

65. Complex Oxalate Ions. 

a. Make a 10 per cent. solution of ammonium ferric sulphate, 
of potassium ferricoxalate, and of potassium ferricyanide. Test 
small samples of each solution with sodium hydroxide. Which 
solutions yield precipitates? Explain. 

b. Pour 5 c.c. of each of the three solutions into separate 
test-tubes. Place the tubes side by side, and add to each 
3 drops of a 10 per cent. solution of potassium thiocyanate. Un- 
der these conditions, this reagent serves as a test for ferric ions 
in the case of ammonium ferric sulphate only. The complex 
ferricoxalate ion is slightly dissociated (cf. a), but has a rather 
large ‘‘stability constant.” 


Fe (C2O4)3"”” << Fett + 3 C.0."". 


This can be demonstrated experimentally as follows: — 
- 62 








§ 66] DIBASIC ACIDS 63 


a. To 5 c.c. of potassium ferricoxalate solution, add three 
drops of the potassium sulphocyanate solution and several 
drops of dilute hydrochloric acid. Explain the appearance of 
the red color. 

To 5c.c. of the ferricoxalate solution, add three drops of potas- 
sium sulphocyanate, and a little calcium chloride. How do you 
explain the appearance of the red color? 

B. To 5c.c. of the ferricoxalate solution, add 1 c.c. of calcium 
chloride solution (10 per cent.). Calcium oxalate is precipitated. 

To 5 c.c. of ferricoxalate solution, add a small piece of solid 
ferric chloride about the size of a pea. After it has dissolved, 
add 1 c.c. of the calcium chloride solution. Is any calcium 
oxalate precipitated? Explain the difference in behavior in these 
two cases. 

c. Interpret these results (a and b) in terms of the law of mass 
action and of chemical equilibrium as applied to the dissociation 
of the complex ferricoxalate ion. What are double salts, and 
how are they distinguished from salts of complex acids? How 
would you classify the three iron salts used in a? 

66. Oxalic Acid as a Reducing Agent. 

a. Mix a crystal of oxalic acid, or an oxalate, with some pow- 
dered manganese dioxide and a little dilute sulphuric acid. What 
gas is evolved? Corroborate your conclusion by an appropriate 
test. 

b. Add a few drops of a dilute solution of potassium perman- 
ganate to a warm solution of oxalic acid containing some dilute 
sulphuric acid. By equations, represent the reaction involved 
in the change. 

c. Action of Light in Accelerating Reduction. Make asolu- 
tion of mercuric chloride containing 0.5 g.in 10 .c.c. of water. Pre- 
pare a second solution containing 0.8 g. of ammonium oxalate in 
20 c.c. of water. Mix these two solutions, and divide the mixed 
solution, placing 15 ¢.c. in each of two test-tubes. Put one of 
these tubes in the sunlight, and the other in a dark cupboard of the 
desk. In the course of a few minutes, the tube in the light will 
become turbid; and, after a short time, a white precipitate will 
form. What is it? Represent the changes by equations. The 
tube in the dark will show no change even after several days. 
How could this reaction be employed to measure the relative in- 
tensities of light from different sources? In the case of the 


64 DIBASIC ACIDS [$ 67 


oxalates of iron, how is this principle put to practical use in 
photography? 

67. Malonic Acid. Place 20 g. of monochloracetic acid in a 
porcelain dish containing 40 c.c. of water. Neutralize the acid 
by adding the calculated amount of sodium acid carbonate. 
Heat the mixture to 50° or 60° until effervescence ceases; then 
add 16 g. of powdered potassium cyanide. Potassium cyanide 
must be handled with great care. This operation must be car- 
ried out under the hood. Precautions must be taken not to 
breathe the vapors which escape; they may contain prussic acid 
and, if so, are very poisonous. After adding the cyanide, stir 
the mixture, and apply a gentle heat until the reaction is 
complete. 

After heating the solution for half an hour, add a solution of 
sodium hydroxide containing 16 g. of hydroxide in 40 c.c. of 
water. Boil the alkaline solution until ammonia ceases to be 
evolved. Add enough water to replace that which passes away 
by evaporation. Finally, neutralize the solution by adding slowly 
that amount of dilute hydrochloric acid which contains 7 g. of 
hydrogen chloride. How can this value be calculated? To 
precipitate the malonic acid, add a solution of calcium chloride 
(30 g.). Filter the calcium malonate, wash it with a little cold 
water, and dry it at 100° until the weight is practically constant. 

To obtain malonic acid, treat a weighed quantity of the dry 
calcium salt with a strong solution of oxalic acid containing the 
calculated amount of oxalic acid. After warming the mixture 
for a short time, filter it, and evaporate the filtrate over a water- 
bath. 

a. Determine the melting-point of the malonic acid which you 
have made. 

b. Heat some malonic acid in a test-tube. What gas is 
evolved? What remains in the tube? 

c. In a distilling-flask with a long neck, heat 1 g. of ethyl 
malonic acid. What gas is evolved? When the fused acid has 
been heated (160°-170°) until gas evolution has ceased, distill 
the remaining liquid, and observe the boiling-point. By appro- 
priate tests, determine what this substance is. 

d. How can the esters of malonic acid be prepared? What use 
is made of malonic ethyl ester in the synthesis of acids of the 
acetic acid series? 


a 








§ 68] DIBASIG ACIDS 65 


68. Fumaric Acid from Maleic Acid. Rearrangement of 
Stereoisomers. Dissolve 0.4 g. of maleic acid in 1 c.c.of water, 
and add a drop or two of bromine to the solution. Divide it 
into two parts. Place one part in the dark and the other in 
direct sunlight. In the course of a few minutes, the tube placed 
in the light will be found to contain a solution turbid with sus- 
pended fumaric acid. In the dark, even after many hours, no 
fumaric acid will separate. 

a. What is maleic anhydride? Does fumaric acid yield an 
anhydride? [RI]. | 

b. What explanation is offered to account for these two 
isomers? How are their space formule chosen? 

c. How can fumaric acid be converted into maleic acid? 

d. Add a few drops of an alkaline solution of potassium per- 
manganate to a solution of maleic acid. (?) 


CHAPTER XIII. 
CYANOGEN AND RELATED COMPOUNDS. 


69. Cyanogen, Dicyanogen. Heat a small quantity of mer- 
curic cyanide in a dry test-tube, and kindle the gas which 
escapes from the tube. What relation does cyanogen bear to 
oxalic acid? [RI]. 

70. Salts of Hydrocyanic Acid or Prussic Acid. 

a. Mercuric Cyanide. Dissolve a little mercuric cyanide in 
water, and add it to a solution of silver nitrate. Try the same 
test, using potassium cyanide instead of mercuric cyanide. 
Explain your observations. 

b. Potassium Ferrocyanide. Dissolve 3.5 g. of ferrous sul- 
phate in 50 c.c. of water. Add 5 g. of potassium cyanide, and 
boil the solution for a short time. Filter the solution, and 
evaporate the filtrate on a water-bath until the salt commences 
to crystallize. When the salt has crystallized from the cold 
solution, collect it, and test it. (?) 

c. How would you convert potassium ferrocyanide into potas- 
sium ferricyanide? How is potassium cyanide made from po- 
tassium ferrocyanide? What is the technical process employed 
in the making of potassium ferrocyanide? How is Prussian blue 
made? 

d. How are alkyl cyanides and alkyl isocyanides related to 
prussic acid? When they are hydrolyzed in the presence of 
dilute mineral acids, what products do they yield? In what 
respects does the behavior of these alkyl derivatives differ from 
that which would naturally be suggested for them by analogy 
through a study of the hydrolysis of such compounds as acetic 
ethyl ester, ethyl nitrite, and ethyl sulphate? From the view- 
point of structure chemistry, and in the language of structural 
formule, can you propose any hypothesis to account for this 
divergence? 

/-71. Cyanic Acid and the Cyanates. Heat a strong solution 
‘of potassium cyanate (not cyanide) with a little sodium hydrox- 
66 





et 














§ 75] CYANOGEN AND RELATED COMPOUNDS 67 


ide. Test the vapors with a piece of neutral litmus paper, and 
notice the odor. Add acid to the remaining solution. What 
gas is evolved? 

a. What relation does cyanic acid bear to carbonic acid? 
Can you illustrate this relation by appropriate graphic formulx? 
What compound bears a similar relation to acetic acid? How 
can potassium cyanide be converted into potassium cyanate? 

72. Methyl Isocyanate. Make a dry mixture of potassium 
cyanate and sodium methyl sulphate, and heat it in a dry test- 
tube. Observe the odor. What products would be obtained by 
the hydrolysis of methyl isocyanate? (Wirtz method of making 
primary amines). Cf. § 70, d. 

73. Cyanic Acid from Cyanuric Acid. In a small distilling- 
flask with a long side tube, place several grams of cyanuric acid, 
previously dehydrated in a beaker upon a water-bath. 

Dip the side tube of the flask into a long test-tube surrounded 
by a freezing-mixture, and heat the bulb until the cyanuric 
acid has almost disappeared. A colorless liquid will be obtained 
in the test-tube. Notice the odor of this liquid. Test a drop 
of it with moist litmus paper. When the liquid becomes warm 
by standing at room temperature, it will suddenly polymerize 
with a decrepitating sound, and will change to a mixture of 
cyanuric acid and cyamelid. [R]. 

Thiocyanic Acid and Isothiocyanic Acid. 

74. Ammonium Thiocyanate. Mix 3 c.c. of carbon disul- 
phide with 15 c.c. of concentrated ammonia water, and add to 
the mixture 15 ¢.c. of alcohol. After two days, evaporate the 
solution to dryness over a water-bath. Extract the thiocyanate 
from the residue by means of hot alcohol. Filter the solution, 
and allow the salt to crystallize from the alcohol. Dry the salt 
upon a piece of porous plate, and make tests to show that it is 
a thiocyanate. 

75. Methyl Thiocyanate. Dimethyl Sulphate as an Alkyl- 
ating Agent. [H]. Dissolve 20 g. of potassium thiocyanate in 
10 c.c. of water. To the cold mixture, add, in two portions, 
26 g. of dimethyl sulphate. Dimethyl sulphate is extremely 
poisonous and has no odor. Exercise great care in working 
with it. Shake the mixture thoroughly and cool it if necessary. 
After the solution has been heated 15 minutes upon a water- 
bath, and has been shaken repeatedly during this time, pour the 


68 CYANOGEN AND RELATED COMPOUNDS [§ 76 


liquid into a separatory-funnel, and remove the ester which will 
accumulate as a lighter layer. Dry it with calcium chloride, 
and distill it. The yield should be about 10g. The ester thus 
obtained will boil between 130°-133°. 

a. What evidence is there to show that a formula in which 
the methyl group is linked to sulphur represents the chemical 
behavior of this ester in a satisfactory manner? 

76. Methyl Mustard-Oil. (Hofmann’s reaction.) Place a few 
crystals of methylammonium chloride in a test-tube, and pour 
upon them several drops of alcohol, 1 drop of carbon disulphide, 
and 1 or 2 drops of a strong solution of potassium hydroxide. 
After a few seconds, add a little water and a slight excess of a 
dilute solution of silver nitrate. When the solution is warmed 
until it boils, the odor of the mustard-oil will become pronounced. 
What are the intermediate products in this reaction? Explain 
their conversion into methyl mustard-oil. 

a. What class of amines may be used in making mustard-oils 
by this method? 

b. What experimental evidence [R] can you mention to justify 
the linking of the alkyl groups to nitrogen in the graphic for- 
mule assigned to mustard-oils? Cf. §72, Methyl Isocyanate. 








as 
4 


CHAPTER XIV. 
UREA AND UREIDS. 


77. Urea. (Wohler’s Synthesis.) Mix a solution of 10 g. of 
potassium cyanate with a solution of 20 g. of ammonium sul- 
phate in 25 g. of water; place the mixture in a porcelain dish, 
and evaporate it to dryness over a water-bath. Powder the dry 
residue, and place it in a small, dry flask connected with a tube 
which serves as an air-condenser. Add 15 c.c. of absolute 
alcohol, and heat the flask on a water-bath until the alcohol 
boils. Pour the hot alcohol through a small filter, leaving the 
residue in the flask. After repeating this treatment with alcohol 
three times, combine the filtrates, place them in an evaporating 
dish, and evaporate them to dryness. Determine the melting- 
point of the dry crystals. What is the melting-point of urea? 

78. Urea from Phosgene. Pour 15 ..c. of ammonia water 
(sp. gr. 0.96) into a small flask, and add to it slowly 10 c.c. of 
a 20 per cent. solution of phosgene in toluene. [H]. Shake the 
flask and cool it if necessary. The solution must react alkaline 
when all of the phosgene has been added. Evaporate the solu- 
tion, and extract the urea as described in § 77. 

These tests are to be performed either with § 77 or with § 78. 

a. Boil a little urea with a strong solution of sodium hydroxide. 
What gas is evolved? Acidify the alkaline solution by adding 
hydrochloric acid, drop by drop. What gas is liberated? How 
do you explain these changes? In what respects does urea re- 
semble acetamide? How can you express the relation which it 
bears to ammonia? to carbonic acid? 

6b. Make a strong solution of urea, about 1 c.c., and add some 
pure concentrated nitric acid to it. Whatisformed? How is it 
possible to obtain urea from this substance? How will a solu- 
tion of ammonia in water react with nitric acid? When you 
take this fact into consideration, what is the probable action of 
nitric acid upon the urea in water solution? 

c. Add bromine to a solution of sodium hydroxide until the 
solution has a deep-yellow color (not red). Fill a test-tube with 

69 


70 UREA AND UREIDS [$ 80 


this solution, and invert it in a dish containing some of the same 
solution. Put 0.5 g. of urea under the test-tube. What gas is 
formed? How is this method employed to estimate urea quan- 
titatively? How would the same reagent act upon ammonia? 

d. Describe one method by which urea could be made syn- 
thetically if you had only carbon, oxygen, chlorine, nitrogen, 
and hydrogen to begin with. Write all equations necessary to 
illustrate the experimental steps. 

e. What is the significance of the terms ureids and diureids? 

79. Biuret and Cyanuric Acid from Urea. Heat one gram of 
urea in a test-tube until the substance melts and evolves a gas. 
Notice the odor of the gas, and test it with moist neutral litmus 
paper. When the evolution of gas has almost ceased, and the 
fused mass has become thick, cool the tube, and digest the 
residue with 3 c.c. of cold water. 

a. Biuret will dissolve, and may be detected by the addition 
of a few drops of a solution of potassium hydroxide and one or 
two drops of a 10 per cent. solution of copper sulphate. Violet- 
red copper biuret will be produced. This is one of the most 
delicate tests for urea. In what sense is biuret related to a ureid? 

b. Cyanuric acid forms the chief product in the tube. After 
washing the residue once more with 5 c.c. of cold water, dissolve 
the remaining solid in a few cubic centimeters of boiling water, 
cool the solution, and add a cubic centimeter of an ammoniacal 
solution of copper sulphate. Copper cyanurate will separate as 
a violet crystalline powder. 

80. Murexid. Mix 0.5 g. of uric acid with one cubic centi- 
meter of concentrated nitric acid (sp. gr. 1.4), place the mix- 
ture in a porcelain dish, and evaporate the solution nearly to 
dryness. Cautiously add a dilute solution of ammonia. The 
ammonium salt of purpuric acid (murexid test) will be formed 
as a purple-red dye. Try the same reaction, substituting caffein 
for uric acid. Is a similar product formed in this case? 








CHAPTER XV. 
POLYATOMIC COMPOUNDS WITH MIXED FUNCTIONS. 


81. Monochlor Acetic Acid. Caution: —Do not get this acid on 
your hands; it produces severe burns. Pour 40 g. of glacial acetic 
acid into a flask containing 6 g. of red phosphorus. Through the 
stopper of the flask, insert a delivery-tube and the end of a 
reflux-condenser. When the flask has been heated in a bath of 
boiling water, conduct a rapid current of dry chlorine gas into 
the acid. The absorption of chlorine will take place quite 
rapidly if the operation is performed in the direct sunlight. If 
it is impossible to arrange the apparatus so that the direct 
sunlight can fall upon it, the same result may be brought 
about somewhat more slowly if a mirror is used to reflect the 
sunlight upon the flask. The reaction will be complete when a 
portion of the chlorinated product, placed in a test-tube, solidi- 
fies on being cooled with ice. 

Transfer the crude product to a distilling-flask, and distill it. 
Allow the vapors to pass through a long ‘‘air condenser,” and 
collect two fractions. The portion which distills between 150° 
and 200° will be chiefly monochlor acetic acid. This fraction 
will crystallize when it has been cooled in a beaker surrounded 
by ice. Transfer the crystals to a Biichner funnel; and, with 
the aid of a pump, separate the liquid from the crystals as 
rapidly as possible. The monochloride may fuse if suction is 
applied too long. A second fraction, boiling between 150° and 
200°, may be obtained by distilling the liquid filtered from the 
crystals. 

The crystals collected in this way should be distilled again. 
About 25 g. of monochlor acetic acid will be obtained. The 
boiling-point of the acid is about 186°. 

a. After finding an appropriate solvent, recrystallize a portion 
of the acid. Determine the melting-point of the pure, dry 
substance. 

b. Dissolve some of the recrystallized acid in a little water. 
To one portion of this solution, add a solution of silver nitrate. 

; 71 


72 COMPOUNDS WITH MIXED FUNCTIONS [§ 84 


Is any silver chloride formed? To a second portion of the solu- 
tion add enough sodium carbonate to neutralize the acid. Boil 
the solution for a few minutes. Add some dilute nitric acid, 
and then some silver nitrate. What are the products formed by 
boiling monochlor acetic acid with dilute alkalies? 

c. Why is phosphorus used in the chlorination of acetic acid? 
What substances may be used in place of phosphorus? What 
other organic compounds are formed during the preparation of 
monochlor acetic acid? 

Alcohol Acids. 

82. Lactic Acid. Distill 5 ¢.c. of lactic acid with 15 c.c. of 
30 per cent. sulphuric acid at 130°. Collect the distillate in a 
cold receiver, and without applying heat test one portion for 
acetaldehyde by means of an ammoniacal solution of silver 
nitrate; test another portion for formic acid, by the addition 
of mercuric chloride and a solution of sodium acetate. Explain 
the decomposition. 

a. What relation does lactic acid bear to propionic acid? 

6b. What is sarcolactic acid? How does it differ from the 
lactic acid obtained from sour milk? 

c. How is the theory of the asymmetric carbon atom em- 
ployed in explaining the isomerism of the lactic acids? 

83. $-Hydroxybutyric Acid. 

a. To a dilute solution of 6-hydroxybutyric acid, add a few 
drops of a 5 per cent. solution of ferrous sulphate and several 
drops of hydrogen peroxide. Cf. §7, Acetoacetic acid. 

b. What significance does this reaction have in connection 
with the chemistry of urine? 

c. What would be found by heating g-hydroxybutyric acid 
with concentrated sulphuric acid? } 

d. What are some of the chief differences observed in the 
chemical behavior of a-, 8-, and y-hydroxyacids? 

/ 84. Tartaric Acid. How is tartaric acid prepared commer- 
cially? How can it be prepared synthetically? 

a. Salts. Calcium Tartrate. Make a solution of sodium 
potassium tartrate. To a cubic centimeter of this solution, add a 
strong solution of calcium chloride. Collect the white precipi- 
tate upon a filter-paper, and wash it thoroughly. Place a little 
of it in a test-tube, and add a strong solution of sodium hy- 
droxide to it. Prepare the sodium hydroxide from a piece of 





e 


a 





“aN 





§ 87] COMPOUNDS WITH MIXED FUNCTIONS 73 


solid hydroxide which has been washed once or twice to remove 
the superficial layer of sodium carbonate. Heat the clear alka- 
line solution of calcium tartrate; a precipitate will form. If the 
sodium hydroxide solution of calcium tartrate is not clear, filter 
it, and then heat it. This is an important reaction in the quali- 
tative test for tartaric acid. (?) 

b. Reduction of the Silver Salt. Place a very small amount 
of calcium tartrate in a test-tube. Add to it a few drops of an 
ammoniacal solution of silver nitrate, and warm the solution 
gently for several minutes. What does this experiment show 
concerning tartaric acid? No equation can be written. 

c. Complex Copper Tartrates. ‘T'o a solution of tartaric acid, 
add several drops of a solution of copper sulphate and make the 
mixture alkaline by adding sodium hydroxide. What is Feh- 
ling’s solution? Repeat the experiment, but in place of copper 
sulphate, use first ferric chloride, then aluminum sulphate. Will 
sodium hydroxide alone cause precipitates when it is added to 
pure solutions of these salts? How do you explain these reac- 
tions? [RI]. 

85. Tartar Emetic. Dissolve 5 g. of potassium hydrogen 
tartrate in 50 c.c. of water. Add 4 g. of antimonious oxide to 
this solution, and boil the mixture. Filter the solution and allow 
it to evaporate until crystals form. 

86. Diacetyl Derivative of Tartaric Ethyl Ester. Mix 6 g. 
of acetic anhydride with 4 g. of the diethyl ester of tartaric 
acid, and add to it 30—40 c.c. of a 10 per cent. solution of sodium 
hydroxide. Mix these substances intimately by thoroughly 
shaking them. .When the odor of acetic anhydride has entirely 
disappeared and a solid has formed, separate the acetyl deriva- 
tive by filtration. Wash it with water, and dissolve it in the 
least possible amount of boiling alcohol. Add water to the hot 
alcohol solution, until it begins to show a slight turbidity; then 
allow the acetyl compound to crystallize. Determine the melt- 
ing-point of the acetyl derivative. It should melt at 67°. 

Ketone Acids. : 

87. Acetoacetic Ethyl Ester. Tautomerism. 

a. Action of Ferric Salts. Add a drop of a dilute solution of 
ferric chloride to an alcoholic solution of acetoacetic ethyl ester. 
Cf. § 63, Acetylacetone; § 127, d, Phenol. 

b. Copper Salt. Shake an ether solution of the ester with an 


* 


74 COMPOUNDS WITH MIXED FUNCTIONS [§ 87 


ammoniacal solution of copper sulphate. Collect the green cop- 
per salt and recrystallize it from alcohol. Cf. § 63, Acetlyacetone. 

c. How is the sodium salt of acetoacetic ethyl ester prepared? 
What views are held concerning the constitutional formule of 
acetoacetic ethyl ester and its salts? What is meant by the 
phrase “enol form”? What is the meaning of the term tau- 
tomerism? 

d. How can acetoacetic acid be made from 6-hydroxybutyric 
acid? What are the products of decomposition when a solution 
of acetoacetic acid is warmed? What significance do these 
facts have in connection with the chemistry of urine? 

e. How can acetoacetic acid be obtained from its ester? 
Describe the reactions involved in the “ketonic splitting” and 
“acid splitting” of alkyl derivatives of acetoacetic ethyl ester. 








CHAPTER XVI. 
CARBOHYDRATES. 


88. Test for Carbohydrates (Molisch’s Test modified by 
Mulliken). Treat avery small crystal of cane-sugar (.05 g.) with 
2 drops of a 10 per cent. solution of a-naphthol in chloroform. 
Down the side of the inclined tube containing this mixture, pour 
2 c.c. of concentrated sulphuric acid so that it may form a dis- 
tinct lower layer. If a carbohydrate is present, a purple-red 
zone will form in the course of a few seconds. After one or two 
minutes, add 5 c.c. of water. A purple precipitate will result. 
Try the same test, but in place of cane-sugar use a small piece 
of starch; of gum ‘arabic: of filter-paper; 3 linen; of d-glucose. 
No equations need be written. 

Reactions with Fehling’s Solution. 

89. Monosaccharides. 

a. Tosix drops of a 10 per cent. solution of d-glucose, add ten 
drops of Fehling’s solution and 3 ¢.c. of water. Boil the solu- 
tion, and continue to add the d-glucose solution until the blue 
color is entirely discharged. 


Note 8.—F¥or the preparation of Fehling’s solution see § 26, 5, 
Acetaldehyde. Fehling’s solution is usually prepared of such a 
strength that each cubic centimeter will oxidize 0.005 g. of glu- 
cose. If 20c.c. of a solution of d-glucose were needed to remove the 
blue color in 10 ¢.c. of Fehling’s solution, how much d-glucose would 
there be in 1 c.c. of the sugar solution? 


6b. In a similar way, try the action of Fehling’s solution 
upon solutions of l-arabinose; of l-xylose; of d-mannose; and of 
d-galactose. If no precipitate separates at once at room tempera- 
ture, boil each mixture for two minutes. 

c. Try the action of Fehling’s solution upon a solution of 
levulose (fruit-sugar). How do solutions of grape-sugar 
(d-glucose) and of levulose (fruit-sugar) differ in their be- 
havior towards polarized light? Why is levulose known as 
d-fructose? 

75 


76 CARBOHYDRATES [§ 91 


90. Disaccharides. 

a. Test a solution of cane-sugar (sucrose, saccharose) with 
Fehling’s solution. If necessary, apply heat for two minutes. 
Result? Add 0.5 ¢.c. of concentrated hydrochloric acid to a 
solution of 5 g. of cane-sugar in 50 c.c. of water. Heat this 
solution on a water-bath for one hour; prevent evaporation as 
much as possible. Neutralize 1 c.c. with sodium carbonate and 
test it with Fehling’s solution. How do you explain the results? 
What is invert-sugar? Why is it given this name? Keep the 
larger portion of the hydrolyzed cane-sugar solution to use in 
experiment 50. 

b. Treat solutions of maltose (malt-sugar) and of lactose 
(milk-sugar) with Fehling’s solution. Result? What important 
conclusions concerning the constitutional formula of the three 
disaccharides used above have been drawn from these experi- 
mental differences? 

91. Polysaccharides. 

a. Starch Solution. Heat 200 c.c. of water to the boines 
point and remove the flame. Mix 1 g. of starch with a little 
cold water, and stir it into the hot water. Test a portion of 
this solution with Fehling’s reagent. Is there any reduction? 
Boil the mixture one minute. Does this cause any precipitation 
of cuprous oxide? 

b. Hydrolysis of Starch. After mixing some of the starch 
paste with about one-tenth its volume of concentrated hydro- 
chloric acid, put it in a flask connected with a reflux-condenser, 
and heat the flask for one hour on a water-bath. Neutralize 
the acid with sodium carbonate, and test the solution with 
Fehling’s reagent. How could this process be employed to 
estimate starch quantitatively? 

c. With Fehling’s reagent, test a solution of gum arabic; of 
dextrin; of glycogen; and a piece of moistened cellulose. Record 
your observations. ds 

d. Hydrolysis of Cellulose. Dissolve piecesof cellulose (filter- 
paper) in cold concentrated sulphuric acid by triturating them 
in a mortar until solution results. Add the acid drop by 
drop. Pour the solution into water, and boil the acid solu- 
tion for half an hour. Neutralize the solution with sodium 
carbonate and test it for hexoses. Does it reduce Fehling’s 
solution? 








§ 93] . CARBOHYDRATES 77 


92. Starch Iodide. 

To some cold starch solution prepared under ‘‘Polysac- 
charides, a,’’ add a drop of a very dilute solution of iodine in 
water containing potassium iodide. Heat the blue solution; 
then cool it. Try this same test, but in place of starch, use a 
solution of glucose; of cane-sugar; of dextrin; of gum arabic; 
and of glycogen. 

93. Phenyl Glucosazone. ‘To the remainder of the solution 
of hydrolyzed cane-sugar (invert-sugar), prepared under ‘‘ Disac- 
charides, a,’ add 8 g. of sodium acetate and 5 g. of phenyl- 
hydrazine. Warm this mixture upon a water-bath for 2 hours. 
Collect the yellow precipitate upon a Biichner funnel, wash it 
with a little cold acetone, and recrystallize it from the smallest 
possible amount of boiling 80 per cent. alcohol. Collect the 
precipitate, dry it upon a piece of porous plate, and determine 
its melting-point. The recorded melting-point is 205°. 

a. What products are found by the hydrolysis of cane-sugar? 

b. How do you explain the fact that only one osazone is 
found in the experiment above? What significance does this 
have in the choice of configurations for the hexose sugars? 


CHAPTER XVII. 
: AMINO ACIDS. 


94. Glycocoll, Glycine, Aminoacetic acid. 

Pour 50 c.c. of a 40 per cent. formalin solution into a 200-c.c. 
flask and add 18 g. of ammonium*chloride. Cool this mixture 
in ice water. Very slowly, and with frequent shaking of the 
mixture, add a cold solution of 22 g. of 98 per cent. potassium 
cyanide in 30 c.c. of water. This process should require about 
3 hours. During the last hour and a half, drop in also 13 c.c. of 
glacial acetic acid. 

Methylene-aminoacetonitrile is formed as a solid, and should 
be collected upon a filter and dried upon a porous plate. The 
yield will be about 60 per cent. of the theoretical amount. 

Cover these crystals with 20 c.c. of cold alcohol previously 
saturated with hydrochloric acid, and, after an hour, add 100 c.c. 
of water. Remove the alcohol by distillation, and evaporate 
the residue to dryness. Recrystallize the product from dilute 
alcohol. The yield, calculated upon the basis of the methylene- 
aminoacetonitrile, should be about 80 per cent. 

a. The Copper Salt. Mix a solution of the glycine salt with 
some freshly precipitated copper oxide, and evaporate it until 
the copper salt commences to crystallize. 

b. Glycine combines with acids, as well as with bases, to form 
salts. What name is applied to inorganic compounds which 
function both as bases and as acids; e.g., aluminium hydroxide, 
zine hydroxide, lead hydroxide? Taking this property of the 
amino acids into consideration, what constitutional formula has 
been proposed for glycocoll itself? 

c. What are leucine, alanine, asparagine? What are poly- 
peptides and how are they obtained from amino acids? What 
relation are they supposed to bear to the proteins? What evi- 
dence is there in support of this view? 


78 








CHAPTER XVIII. 


COLLOIDS. 


95. I. Suspension Colloids (Suspensoids; Hydrophobic or 
Lyophobic Colloids). 

a. Colloidal Ferric Hydroxide. Examine the colloidal solu- 
tion of ferric hydroxide which has been given you. Does the 
solution appear to be homogeneous? 


Note 9.— This solution may be prepared by adding ammonium 
hydroxide to a fairly dilute solution of ferric chloride until the 
solution of the ferric salt is just neutralized. Place the solution in 
a dialyzer, and dialyze it against distilled water for some ten days, 
until the dissolved salts are eliminated. 


Do you notice any appreciable change in homogeneity when 
some of the colloidal solution is diluted with large or small quan- 
tities of water? Examine a drop of the colloidal solution under 
an ultramicroscope or a dark ground microscope. What do 
you observe? 

b. Influence of the Electric Current. Pour some of the col- 
loidal solution of ferric hydroxide into a small U-tube having a 
rather long connecting arm of small diameter; insert platinum 
electrodes into the arms of the U-tube, and attach the ter- 
minals of the electrodes with several cells connected in series. 
When a current is passed, what happens immediately? after 
several minutes? after an hour? after several hours? What 
do you conclude from this behavior? 

c. Precipitation of the Colloid. Effect of Salt Concentra- 
tion. For the following experiments, it will be necessary to have 
one or two 5-c.c. pipettes graduated to 0.1 ¢.c., and a 25-c.c. grad- 
uated cylinder or flask. The salt solutions used here and under 
d are all molar.* Starting with a M/10 solution of sodium chlor- 
ide, prepare 10 c.c. of solutions of approximately the following 


* In all of the experiments which follow, N is used to designate equiv- 
alent normal solutions; and M, in all cases, to signify molar solutions. 


79 


80 COLLOIDS [$ 96 


concentrations: — 1/20; 1/50; 1/100; 1/200; 1/300 M. Place 
these solutions in labeled test-tubes arranged in the order of 
increasing concentration, together with a tube containing 10 c.c. 
of distilled water for comparison. Drop 0.5 c.c. of the colloidal 
solution of ferric hydroxide into each tube. In the course of a 
few minutes, do you observe any change in the appearance of the 
tubes? Keep these tubes for experiments described later under e. 

d. Comparison of Precipitates Produced by Various Anions 
and Cations. With concentrations the same as those used in 
c, prepare a similar series of five tubes with each of the following 
salt solutions: —M/10 sodium bromide; M/10 sodium iodide; 
M/10 sodium phosphate (Na,HPO,); M/10 sodium sulphate. 
Add to each solution 0.5 c.c. of colloidal ferric hydroxide solution. 

In a similar way, investigate solutions made by diluting a 
M/10 solution of sodium chloride; a M/10 solution of calcium 
chloride; a M/10 solution of barium chloride; a M/10 solution of 
aluminium chloride. When solutions of the different salts of 
the same concentrations (e.g., M/100) are compared, do you 
notice any difference in the precipitating effect produced by 
anions and by cations of different positive and negative values? 

e. Heat Effect. Heat some of the tubes in which no pre- 
cipitates formed. Do not boil the solutions. Does this cause 
precipitates to form? Reserve other solutions in which no 
precipitates were produced, and examine them the next day. 
Have precipitates formed in any of these tubes? What do you 
conclude regarding the time element in the precipitation of 
colloids? 

f. Colloidal Metals and Sulphides. If practical, these ex- 
periments may be tried with a colloidal solution of silver; of 
platinum; of one of the metallic sulphides, e.g., arsenious sul- 
phide. 

96. II. Emulsion Colloids (Emulsoids; Hydrophilic or 
Lyophilic Colloids). 

a. Swelling and “Solution” of Emulsoids. Examine 
samples of the following solids: — Egg albumin, gelatine, fibrin, 
gluten, casein, and starch. Drop a small amount of each of 
these solids into separate test-tubes, and pour a little water 
upon each sample. Notice that after a time some of the samples 
swell. | 
Now, warm them all, at first slightly, and then until the 





§ 96] COLLOIDS 81 


water boils. - Observe that with this treatment others swell, 
while some apparently go into solution; and that these liquids 
are then miscible in any proportion with water to give solutions 
apparently clear. 

6. Homogeneity. Examine drops of these solutions under 
an ultramicroscope. What differences do you notice when you 
compare the results obtained here with the results obtained 
with the colloidal solution of ferric hydroxide? 

c. Effects of Salt. With asolution of egg albumin, prepared 
by filtering a solution made by treating white of egg with some 
ten times its volume of water, repeat some of the experiments 
with the various salt solutions described above under ferric 
hydroxide. What results have you obtained? How do they 
differ from the results obtained with the ferric hydroxide 
solution? 

d. Nature of Certain Albumin Tests. ‘T'o the solution of egg 
albumin, add a concentrated (saturated) solution of magnesium 
sulphate, or of sodium sulphate. How does a solution of ferric 
chloride, or of dilute acetic acid and potassium ferrocyanide, 
affect the albumin solution? What is the action of concentrated 
nitric acid upon it? When these changes are considered, what 
would you say concerning the nature of some of the ordinary 
tests for albumin? 

e. Swelling of Fibrin Produced by Acid. Choose five test- 
tubes of uniform diameter, and place in them respectively 20 c.c. 
of N/250, N/230, N/220, N/210, N/200 hydrochloric acid. To 
this series, add another tube containing 20 c.c. of distilled water. 
In each tube place 0.2 g. of finely powdered blood-fibrin, care- 
fully weighed. Shake the tubes occasionally, and inspect them 
at intervals during a period of 24-48 hours. What changes 
take place in the appearance of the fibrin? Do the acids of 
different concentrations affect fibrin in the same way? Is there 
any relation between swelling and concentration of acid? 

f. Swelling of Fibrin Produced by Alkali. Prepare a similar 
series of tubes containing solutions of sodium hydroxide, or of 
potassium hydroxide, equivalent in concentration to the acid 
solutions previously employed. Add to each tube 0.2 g. of 
fibrin as before. How does the swelling in alkaline solution 
compare with that observed in acid solution of equivalent con- 
centration, or in distilled water? 


82 COLLOIDS [$ 96 


g. Influence of Salts upon Swelling Induced by Acids and 
by Alkalies. Into each of five test-tubes, pour 20 c.c. of N/200 
hydrochloric acid; add to these tubes respectively 1, 2, 3, 4, and 
5 ¢.c. of a molar solution of sodium chloride, and enough dis- 
tilled water to make the total volume 25 c.c. For comparison, 
prepare two other tubes, one containing 20 ¢.c. of N/200 hydro- 
chloric acid diluted to 25 ¢.c.; and the other, 25 ¢.c. of distilled 
water. Into each of the seven tubes put 0.2 g. of blood-fibrin 
carefully weighed. When the tubes have stood for some time, 
what conclusions do you draw concerning the effect of sodium 
chloride upon the swelling of fibrin in acid solution? 

h. Influence of Anions and Cations upon Swelling. Pre- 
pare two more series of tubes containing 20 c.c. of N/100 hydro- 
chloric acid as before under g. Here, however, instead of adding 
different concentrations of the same salt, use the same -con- 
centrations of different salts, first with dissimilar anions, and 
then with dissimilar cations. 

To five of the tubes containing acid, add respectively the same 
volume of molar solutions of sodium chloride, sodium bromide, 
sodium sulphate, sodium iodide, sodium phosphate. Arrange 
these tubes beside the comparison tubes containing pure acid 
and distilled water. To each of the seven tubes add 0.2 gram 
of blood-fibrin. 

Prepare a-second series of seven tubes, and to five of the tubes 
containing acid, add the same volume of molar solutions of sodium 
chloride, calcium chloride, barium chloride, magnesium chloride 
and aluminium chloride. To each of the tubes including the com- 
parison tubes of pure acid and water, add 0.2 gram of fibrin. 

Record and compare your results. What are saline cathar- 
tics? What are saline diuretics? How do they affect colloids? 

1. Non-Electrolytes and Swelling. Perform a series of ex- 
periments with fibrin and N/200 hydrochloric acid; but use 
osmotically equivalent solutions of ethyl alcohol or methyl 
alcohol, of glycerol, of urea, in place of the electrolytes em- 
ployed above. Solutions of the non-electrolytes which have 
twice the molar concentration of the solutions of electrolytes 
found active above will be accurate enough. Since the dissoci- 
ation of the salts in molar solution is less than 90 per cent., the 
use of double molar solutions would favor the non-electrolytes 
provided the effect is an osmotic one. What are the results? 





§ 96] COLLOIDS 83 


j. The Swelling of Dried Gelatine Plates. Absorption 
Curves. After carefully weighing plates of dried gelatine, drop 
one of them into a dish containing 100 c.c. of N/20 hydro- 
chloric acid, and another into a dish containing 100 c.c. of 





Fig. 18. 


N/20 sodium hydroxide. Place one more of these weighed 
plates in 100 c.c. of distilled water. From time to time, weigh 
the plates and record the weights. 
This process should extend over 
a period of 2-3 days. Plot ab- 
sorption curves with values cal- 
culated in percentage of change 
based upon the original weights 
of the dried plates as ordinates, 
and the times as abscisse. 
| Thefollowing curvestaken 
from Dr. Martin H. Fischer’s 
work ‘‘Gidema’’ will serve to il- 
lustrate the method of plotting 
such curves. Fig. 18 illustrates 
the effect of certain acids and 
alkalies upon gelatine. Fig. 19 
illustrates the effect of salts in 
“ 2» modifying the swelling of gelatine 
produced by acids and by alkalies. 


— Gelatine — 





Fig. 19. 


Note 10. — The Making of Gelatine Plates. Dissolve one part 
of the best commercial gelatine (Ne Plus Ultra Gelatine of the 


84 COLLOIDS [§ 96 


Deutsche Gelatine Fabriken serves the purpose well) in 4 parts of 
water at a temperature of about 45°. Pour this solution into 
shallow pans. Allow the gelatine to harden in an ice-chest. With 
the aid of a sharp knife and a ruler, cut the gelatine into plates 
of uniform size (2.5 cm. square). Allow the squares to dry upon 
glass plates in a warm place (30°-40°). This operation will require 
from 6-10 days. The plates may conveniently be made of such a 
size that, when dry, they measure about 18 X18 X2.6 mm. They 
will weigh about 0.8g. Uniform material is essential, if comparisons 
are to be made from which valid conclusions may be drawn. 











PART II. 
AROMATIC COMPOUNDS. 


DIVISION 1. CARBOCYCLIC COMPOUNDS. 
DIVISION 2. HETEROCYCLIC COMPOUNDS. 





SA 
_ 
= ~ee tr ; = 
* ‘| 
cis 

= Bot. a. ~ 
a —* ty . > 

= ® « all | 

i 


‘ 


My 


ay iy 


ly 


oe? 








Po g 
ci 
< 5 . } e 
2 ae P : i 


CHAPTER XIX. 


BENZENE HYDROCARBONS. 


oe 97. Benzene. 

a. Treat 2 c.c. of benzene with a few drops of a solution of 
bromine in carbon tetrachloride. What do you observe? Com- 
pare ve behavior with that observed in the case of amylene. 
(Cf. § 6.) 

b. Shake 2 c.c. of benzene with a dilute solution of potassium 
permanganate made slightly alkaline by means of sodium car- 
bonate (von Baeyer’s reagent). Compare this case with the 
reaction of ethylene and olefine hydrocarbons toward the same 
reagents. 

c. Add a few drops of bromine to 10 c.c. of benzene, and 
pour equal portions of this solution into each of two dry test- 
tubes. To one tube, add some iron filings. What differences 
do you observe in the velocity of the action in the two tubes, 
as shown by the evolution of hydrogen bromide? 

Is the product formed by the action of one equivalent of 
bromine upon benzene to be considered as a substitution prod- 
uct, or as an addition product? (?) 

d. What is Kekulé’s constitutional formula for benzene? 
In these reactions, does benzene seem to show the behavior 
which is so typical of an unsaturated hydrocarbon of the ali- 
phatic series? 

98. Benzene Sulphonic Acid. 

Pour 3 c.c. of benzene and 10 c.c. of concentrated sulphu- 
ric acid into a large test-tube; close the tube with a stopper 
through which a long glass tube, or air-condenser, passes. Shake 
the tube, and heat it gently until the benzene, which at first 
floats upon the surface of the acid, has entirely dissolved. Pour 
a little of this solution into a beaker of water. Does benzene 
separate when the solution has cooled? Pour the remainder of 
the solution into about four times its volume of a saturated 
solution of sodium chloride. Crystals of the sodium salt of ben- 

87 


88 BENZENE HYDROCARBONS [§ 98 


zene sulphonic acid will be precipitated. Collect these crystals 
on a Biichner funnel; wash them with a little cold water, and dry 
them. Preserve this salt for a later experiment. (See § 127, c, 
Phenol.) 

a. Shake several drops of toluene with one or two cubic 
centimeters of fuming sulphuric acid, and pour the homogeneous 
solution into water. Try the same experiment with petroleum 
ether (benzine). What difference do you observe? Is this a 
distinctive criterion by which one may judge of the chemical 
nature of a hydrocarbon; or do the two classes of hydrocarbons, 
represented by benzene and petroleum ether respectively, re- 
spond to the action of concentrated sulphuric acid in a similar 
manner, but with great disparity in velocity? 








CHAPTER XX. 
NITROBENZENE AND SOME OF ITS REDUCTION PRODUCTS. 


“+ 99. Nitrobenzene. Put into a flask 35 c.c. of ordinary con- 
centrated nitric acid (sp. gr. 1.41), and add to it carefully 40 c.c. 
of concentrated sulphuric acid. Cool the mixture under the 
water-tap, and add 25 g. of benzene in five or six portions, and 
with constant shaking of the mixture. The introduction of 
the benzene should take about half an hour. Then warm the 
flask at a temperature of 60° on a water-bath for half an hour, 
and shake it from time to time. The nitrobenzene should float 
upon the mixture. 

Now pour a drop of the contents of the flask into water, and 
note whether the oil sinks or floats. If the oil is practically 





free from benzene, it will sink. If the nitration of the benzene 
has been successful, pour the product into a flask containing 
about 500 ¢.c. of water. Shake the mixture thoroughly, cool it, 
and separate the lower layer of nitrobenzene by means of a 
separatory-funnel. 

Wash the nitrobenzene with water, and dry it thoroughly with 
fused calcium chloride. Then distill it, using a condenser with- 
out a water-jacket. The first cubic centimeter or two will be 
chiefly benzene and a little water. This should be collected 

89 


90 NITROBENZENE [§ 102 


separately, and should not be allowed to run through the clean 
condenser-tube. When these impurities have volatilized, the 
temperature will rise rapidly to the boiling-point of nitrobenzene. 
At this point, connect the distilling-flask with the condenser- 
tube, and distill the liquid until the residue in the flask becomes 
thick and dark brown in color. What is the observed boiling- 
point? 

a. Is this a general method for preparing aromatic nitro- 

compounds? Can any of the aliphatic nitro-compounds be 
made in a similar way? What commercial value does this 
reaction have? What nitrating agents are commonly employed 
in technical work? 
/ 100. Meta-dinitrobenzene. Mix 3 drops of benzene with 
i c.c. of concentrated nitric acid (sp. gr. 1.4) and 1 c.c. of con- 
centrated sulphuric acid (sp. gr. 1.84). Boil the mixture gently 
for one-half minute. Pour the product into 10 c.c. of water, 
collect the precipitate upon a small filter, and wash it until 
the washings are colorless. Dissolve the crystals in 8 c.c. of 
boiling dilute alcohol (equal parts of water and alcohol). Set 
the tube aside, and allow the solution to cool; long needles of 
meta-dinitrobenzene will form. Collect these crystals upon a 
filter, wash them with 5 c.c. of dilute alcohol (1:1); dry them, 
and determine their melting-point. The recorded melting-point 
is 90°. Small quantities of benzene may be identified by this 
reaction. 

101. Azoxybenzene. Dissolve 15 g. of nitrobenzene in 
125 c.c. of methyl alcohol, and add to it 20 g. of powdered 
‘sodium hydroxide. Heat the mixture for two hours upon an 
actively boiling water-bath. Remove most of the methyl 
alcohol by distillation, and pour the dark residue into ice water. 
Azoxybenzene will separate as an oil, which, however, will soon 
solidify. Collect the solid upon a Biichner funnel, and wash it. 
After shaking this residue with some warm dilute hydrochloric 
acid for a few minutes, cool it until it solidifies once more; 
collect it upon a filter and wash it. To purify this crude azoxy- 
benzene still further, recrystallize it from warm alcohol (90 
per cent.). The melting-point is 36°. 

102. Azobenzene.* Pour 125 c.c. of methyl alcohol into 
a flask (about 1-liter) and add 12.5 g. of nitrobenzene. Connect 


* Suggested by Dr. H. S. Fry, University of Cincinnati. 


ae i * _ at 
© Ms Cea ar 








§ 104] AND ITS REDUCTION PRODUCTS 91 


the flask with a reflux-condenser, and add 7.4 g. of powdered 
magnesium. If the action does not commence at once, a crys- 
tal of iodine may start it. The vigorous action which fol- 
lows should be controlled by submerging the flask in cold 
water. The reaction requires ten or fifteen minutes for com- 
pletion; the end is reached when the odor of nitrobenzene has 
disappeared. 

After removing most of the methyl alcohol by distillation, 
transfer the residue to an evaporating-dish, and heat it upon a 
steam bath until it becomes dry. Pulverize 
the residue and extract the azobenzene with 
ether, preferably in a Soxhlet apparatus. When 
the ether is removed, recrystallize the azoben- 
zene from methyl alcohol. The melting-point 
is 68°. The yield should be about 95 per cent. 
of the calculated amount. 

a. Is azobenzene a ‘‘dye”? Why isit called 
a chromogen? What is a chromophor group? 
an auxochrome group? 

103. Hydrazobenzene. Dissolve the azo- 
benzene in boiling alcohol, and add zine dust 
to it in small portions until the red color is 
entirely discharged. Filter the hot solution 
rapidly. To the filtrate, add hot water which 
contains a little sulphurous acid (?) until the 
solution becomes slightly turbid; then set it 
aside, and allow the hydrazobenzene to separate 
as the solution cools. Collect the precipitate 
. upon a filter, wash it with water containing 
sulphurous acid, and dry it. The melting- 
point is 126°. 

a. How can hydrazobenzene be changed to 
azobenzene? to aniline? 

b. Does hydrazobenzene reduce Fehling’s 
solution? 

104. Benzidine Salts. ‘‘ Benzidine Rearrangement.’ The 
hydrazobenzene obtained above should be treated with one and 
a half times its weight of concentrated hydrochloric acid and 
twice its weight of water, and then boiled gently for a few min- 
utes. When the acid solution is cooled, benzidine hydrochloride 





Fig. 21. Soxhlet 
Extractor. 


92 NITROBENZENE [§ 105 


will separate. Collect the crystals upon a filter and purify 
them by recrystallization from water. 

Add a few drops of sulphuric acid to the filtrate. Benzidine 
sulphate is soluble with difficulty, and will separate. 

a. How could you prepare benzidine from its salts? How 
is benzidine employed in making dyes? 

_ 6. Does benzidine hydrochloride reduce Fehling’s solution? 

105. Aniline. Into a 500-c.c. flask put 15 g. of nitrobenzene 
and 27 g. of granulated tin, and add, in small portions, 100-150 
e.c. of strong hydrochloric acid. Shake the flask frequently. 
The mixture will become so warm that the reaction must be 
controlled by occasionally cooling the flask. The reaction will 
be complete when the odor of nitrobenzene has almost dis- 
appeared. During the course of the experiment, a white double 
salt of tin chloride and aniline chloride will usually separate. 
At the close of the operation, add water enough to dissolve this 
salt; then pour off the solution, leaving the excess of tin in the 
flask. Tio remove any unchanged nitrobenzene, cool the solu- 
tion thoroughly, place it in a separatory-funnel, and extract it 
two or three times with small portions of ether. This ether 
extract should be thrown away. What does it contain, and 
why is the extraction desirable? 

To the acid solution separated from the ether, add solid 
caustic soda until the stannic acid and stannous hydroxide 
which form at first are almost redissolved. Care! If the solu- 
tion grows very warm, cool it immediately before you add any 
more sodium hydroxide. Most of the aniline will separate as 
an oil. It will be safer, however, to add the sodium hydroxide 
until the solution reacts strongly alkaline towards litmus. In 
some cases, the oil may not separate, but may remain com- 
pletely dissolved. 

Arrange an apparatus like the one described under chloroform, 
and distill the aniline in a current of steam until no more oil 
drops pass over. Extract the distillate with ether, and dry 
the ether solution with solid sodium-hydroxide; then filter it, 
distill the ether from a water-bath, and fractionate the aniline 
in a small distilling-bulb. The condenser needs no jacket. 
What yield have you obtained? 

a. What relation does aniline bear to benzene? to ammonia? 
to methylamine? 





§ 107] AND ITS REDUCTION PRODUCTS 93 


b. Shake a drop of pure aniline with a few cubic centimeters 
of pure distilled water (ammonia free), and test the clear solution 
with a piece of neutral litmus paper. What is the reaction? 

c. Add some of this solution to a solution of ferric chloride; 
of zinc chloride; of aluminium chloride. In view of the reaction 
shown in b, how do you account for the observations which you 
have made with these salt solutions? 

d. Dissolve a drop of aniline in the least possible amount of 
dilute hydrochloric acid. Why does aniline dissolve easily in 
acids, while it is soluble with difficulty in water? Add a few 
drops of this acid solution to a solution of hydrochlorplatinic 
acid. What is the formula of the compound which is pre- 
cipitated? [R]. Does ammonium chloride react in a similar 
way with hydrochlorplatinic acid? (Cf. § 52, Methylammonium 
Chloride.) 

106. Phenylammonium Chloride, Aniline Hydrochloride. 
Pour 15 g. of freshly distilled aniline into a mortar, and add to 
it a little more than one equivalent of pure hydrochloric acid in 
the form of concentrated acid (sp. gr. 1.18). When the two © 
substances have been thoroughly mixed by rubbing them to- 
gether with a pestle, cool the product and collect. the salt upon 
a Buchner funnel. Drain the salt thoroughly upon a Biichner 
funnel by applying suction with a filter-pump, and dry the solid 
in a beaker upon a water-bath. This salt will be needed for 

later experiments. Cf. § § 109, 112. 

: 107. Hydrolysis of Aromatic Amine Salts. 

a. Test a solution of pure aniline hydrochloride in water 
with Congo red paper, then with neutral litmus paper. Explain 
your results. Are any oil drops of aniline visible in this 
solution? 

b. Dissolve about 0.5 g. of para-nitraniline in the smallest 
possible amount of boiling concentrated hydrochloric acid. 
Filter the hot solution and cool it under the tap; the hydro- 
chloride of para-nitraniline will be precipitated. Collect the 
crystals upon a filter and dry them thoroughly to remove all 
traces of free hydrogen chloride. Transfer them to a watch- 
crystal, and moisten them with a few drops of water. How 
do you explain the change of color? With neutral litmus 
paper, test the liquid which surrounds the yellow precipitate. 
Explain your observations. 


94 NITROBENZENE, ETC. [§ 108 


c. Dissolve a few crystals of diphenylamine in a little alcohol, 
and pour the solution into water. Add concentrated hydro- 
chloric acid, a drop at a time, until the diphenylamine dissolves. 
If water is added to the clear solution, diphenylamine will be 
precipitated. Explain. 

d. From the observations which you have just made, what 

seems to be the influence of nitro groups and of phenyl groups 
upon the base-forming power of aniline? Is there any generali- 
zation covering these cases and others of a similar nature? 
Cf. Appendices D and E. 
* 108. Acetanilide, Antifebrin. Put 5 g. of aniline and 7 g. 
glacial acetic acid in a small flask, connect the flask with a 
reflux-condenser, and heat the flask over a wire gauze. The 
mixture should boil gently for 4 or 5 hours. 

At the end of this time, pour the product into 200 c.c. of cold 
water. Filter the mixture, wash the crystals with dilute hydro- 
chloric acid, and recrystallize the acetanilide from hot water. 
If the crystals are colored, add a small amount of animal char- 
coal to remove the color during the process of recrystallization. 
Dry some of the crystals and determine the melting-point. 
Acetanilide is known as antifebrin. 

a. Heat some of the crystals with a strong solution of sodium 
hydroxide. What is formed? Boil a few crystals with dilute 
sulphuric acid (1:1). Notice the odor of the vapor. (?) | 

b. How does acetanilide differ from aniline acetate? Is 
aniline acetate formed in this preparation? What would be 
obtained by heating ammonium acetate? 

c. Heat 2 c.c. acetyl chloride with 1 ¢.c. of aniline, and treat 
the product with water. Separate the crystals and recrystallize 
the substance from a little boiling water. Compare the melting- 
point of these crystals with the melting-point of a sample of 
acetanilide prepared above. 

d. Warm 1 ¢.c. of acetyl chloride with 1 c.c. of monomethyl- 
aniline; then heat 1 c.c. of acetyl chloride with 1 c.c. of dimethyl- 
aniline. Pour each product into water. Is there evidence of 
chemical change in each case? Are the reactions illustrated in 
c and d typical of primary, secondary, and tertiary amines in 
general? 








CHAPTER XXI. 
DIAZONIUM SALTS AND DIAZO COMPOUNDS. AZO-DYES. 


Diazonium Compounds. 

109. Benzene Diazonium Chloride (Solid). Make a solution 
of 5g. of solid aniline hydrochloride in 35 c.c. of absolute alcohol 
containing a few drops of hydrochloric acid. Cool it until the 
temperature is about +5°, and add 6 g. of amyl nitrite. This 
process is called diazotizing. 

The success of the operation may be determined as follows: — 
To a drop of the solution, placed upon a water-glass, add a drop 
of a solution of sodium acetate; a yellow precipitate will indicate 
an excess of the aniline salt and insufficient nitrite. If this 
should be the case, add a little more nitrite, and apply the test 
with acetate again. Finally, sodium acetate should give no 
yellow precipitate; but, even after long standing, a drop of the 
solution placed on a water-glass must give a blue color with a 
little starch solution containing potassium iodide. (?) 

To promote the separation of the diazonium salt, add a few 
drops of ether. (?) Collect the precipitate upon a funnel, and 
wash it with ether. Dry a very small amount of it, and heat 
it upon a metal spatula. (Explosive!) Dissolve the remainder 
at once in 50 c.c. of water cooled to +5°. 

110. Benzene from a Diazonium Salt. The diazonium chlo- 
ride solution prepared in the previous experiment should be 
poured into a cold solution of sodium hydroxide containing 10 g. 
of sodium hydroxide dissolved in 30 ¢.c. of water. Make an alka- 
line solution containing 20 g. of stannous chloride (SnChk, 2 H.O), 
and add it gradually to the former solution. When the resulting 
mixture is distilled, benzene and water vapor will pass over. 
About 4 g. of benzene can be separated from the distillate. This 
method is frequently employed to convert amino-compounds 
into hydrocarbons; or, expressed in hypothetical terms, “to 
eliminate amino groups.”’ Alcohol is sometimes employed as 
a reducing agent in place of stannous chloride. 

95 


96 DIAZONIUM SALTS [§ 111 


Benzene may be identified by its boiling-point, or by con- 
version into m-dinitrobenzene. (Cf. § 100.) 

a. What is Sandmeyer’s reaction? 

b. By the intermediate formation of diazonium salt, how 
could aniline be changed into phenol? into iodobenzene? into 
benzonitrile? 

Diazo Compounds. 

111. Para-nitrophenyl-antidiazotate. Dissolve 7 g. of 
p-nitraniline in 25 ¢.c. of hot dilute hydrochloric acid (1:1); 
pour this solution upon crushed ice, and add 4 g. of sodium 
nitrite dissolved in 13 c.c. of water. Some ice should 
remain at this point. To make sure that sufficient nitrite 
has been used, apply the test with sodium acetate described 
in § 109. 

When enough nitrite has been added, stir the turbid solution 
until it becomes practically clear, and filter it rapidly through 
a funnel containing a loose plug of cotton. Test the filtrate to 
make sure that sufficient nitrite has been used. Dissolve about 
20 g. of sodium hydroxide in 200 c.c. of water; and, with the 
temperature of this solution at 60°, pour the diazonium solution 
rapidly into it. Golden-yellow crystals of sodium p-nitrophenyl- 
antidiazotate will separate abundantly when the mixture is 
thoroughly cooled. 

Collect the crystals upon a Biichner funnel, and wash them 
carefully with a little ice-cold water. Dissolve them in 90 per 
cent. alcohol at a temperature not exceeding 60°. Filter the 
solution, and allow it to stand until the salt crystallizes. The 
yield will be about 6g. The corresponding syndiazotate has 
not been prepared. (Schraube and Schmidt, Ber. 27, 518.) 

a. Make a dilute water solution (30 ¢.c.) of the sodium anti- 
diazotate, and pour 5 c.c. of it into an alkaline solution of 
e-naphthol; of 6-naphthol. 

b. Acidify 5 c.c. of the solution of the antidiazotate by adding 
dilute hydrochloric acid until the solution reacts distinctly acid. 
What does this solution contain? Pour some of this acidulated 
solution into an alkaline solution of e-naphthol; of 6-naphthol. 
The alkali must be in excess. 

c. Acidify 5 c.c. of the original solution of the antidiazotate, 
but make it distinctly alkaline before you pour it into an alkaline 
solution of a-naphthol; of 6-naphthol, 








§ 113] AND DIAZO COMPOUNDS. AZO DYES’ 97 


d. What are syndiazotates?» What réle do they play in the 
formation of azo-dyes? How are they changed into anti- 
diazotates? How are antidiazotates changed into diazonium 
salts? into syndiazotates? In view of these relations, explain 
the observations which you have made in performing experi- 
ments a, b, and c above. 

Azo Dyes. 

112. Benzene Diazonium Chloride Solution. To a mixture 
of 21.5 c.c. (24 mols) of concentrated hydrochloric acid (sp. gr. 
1.18) and 20 c.c. of water, add 10 g. of aniline (1 mol). Put 
into this solution enough crushed ice to keep the temperature 
of the solution below 10° during the following operation. Dis- 
solve 7.7 g. of sodium nitrite in 20 c.c. of water, and add it 
slowly to the solution of the aniline salt. At the end of this 
process, called “diazotizing,’ there should be some ice left. 
A sample of this product placed upon a watch-crystal and 
treated with an excess of a solution of sodium acetate, should. 
give no yellow color or precipitate. The appearance of a yellow 
precipitate or color indicates insufficient nitrite; should this 
occur, add a little more nitrite solution, and test the diazo 
solution again. When enough nitrite is present, a drop of the 
diazonium chloride solution, when brought in contact with 
starch and potassium iodide, should show the starch-iodide test, 
if not immediately at least after a short time. In the prepara- 
tion just described, what is the yellow precipitate formed by the 
addition of sodium acetate? 

113. ‘* Coupling ’’ of Diazo Compounds with Amines and 
with Phenols. 

a. With amines. To a water solution of dimethylaniline 
hydrochloride, add a little of the diazonium chloride solution 
and a slight excess of sodium acetate solution. Pour some of 
the diazonium chloride into an alcoholic solution of a-naphthyl- 
amine and of 6-naphthylamine, and add an excess of sodium 
acetate. What are the products formed in these reactions? 

b. Add some of the diazonium chloride solution, first to a 
solution of naphthionic acid dissolved in an excess of sodium 
hydroxide, and then to a solution of naphthionic acid in an 
excess of sodium acetate. 

c. With phenols. Add some of the diazonium chloride so- 
lution to solutions of phenol; of resorcinol; of a-naphthol; of 


98 DIAZONIUM SALTS [§ 115 


6-naphthol. These substances should be employed first in acetic 
acid or alcohol solution; second, in acetic acid with an excess of 
sodium acetate; third, in a dilute solution of sodium hydroxide. 
Explain the reactions in each case. 

114. Diazoaminobenzene. Pour one-half of the diazonium 
chloride solution prepared in § 113 into a beaker cooled by sur- 
rounding it with ice, and add 6 g. of solid aniline hydrochloride. 
(Cf. §106.) Make a concentrated solution of sodium acetate 
containing 23 mols and add it to the solution made above. 
After an hour or two, collect the precipitate upon a funnel 
connected with a filter-flask and pump; drain it thoroughly 
and wash it with water. When it has been dried upon a porous 
plate, recrystallize it from low-boiling ligroine or gasoline. A 
flask connected with a reflux-condenser should be employed 
in this process. Diazoaminobenzene should form golden-yellow 
erystals, which should melt at 98°. The yield should be about 
70 per cent. of the amount calculated. 

a. Dissolve a small amount of diazoaminobenzene in alcohol, 
and add to it an alcoholic solution of silver nitrate. 

b. Treat a little of the diazo-compound with dilute hydro- 
chloric acid. Treat a second portion with hot concentrated 
hydrochloric acid. Explain these changes. 

115. Aminoazobenzene. Mix 1 g. of diazoaminobenzene 
with a little aniline hydrochloride (0.5 g.), and add to it about 
twice its volume of aniline. Heat this mixture at a temperature 
of about 40°-50° for 15-30 minutes. Pour this reaction product 
into an excess of very dilute acetic acid. Collect the separated 
solid and wash it with water. Boil the precipitate with 200 c.c. 
of water, and add concentrated hydrochloric acid cautiously 
until a sample of the deep-red liquid when cooled will deposit 
steel-blue needles. Filter the hot solution, and allow it to stand 
and cool until the crystals of the hydrochloride of aminoazoben- 
zene have separated. 

Aminoazobenzene itself may be made from the salt suspended 
in twice its volume of alcohol, by the action of concentrated 
ammonium hydroxide, added drop by drop, until the salt is 
dissolved and the color of the solution becomes brown. By 
careful treatment with water, aminoazobenzene will separate 
in yellow crystals. It may be recrystallized from dilute 
alcohol. 








§ 118] AND DIAZO COMPOUNDS. AZO DYES 99 


a. Immerse a piece of white woolen yarn in a hot solution 

of the hydrochloride of aminoazobenzene. After 10 minutes 
remove the yarn and wash it. Is it dyed? Can the color be 
removed by washing? 
_\116. Bismarck Brown. (First Azo-dye, 1866.) Make a 
dilute solution of meta-phenylenediamine, add to it a small 
crystal of sodium nitrite and a drop of dilute sulphuric acid. 
What is the nature of the reaction? How is this reaction em- 
ployed to detect and to estimate very small quantities of nitrites 
in drinking-water? 

“117. Helianthin. (Methyl Orange.) Dissolve 4.3 g. of sul- 
Piinilic acid in a dilute solution of sodium hydroxide con- 
taining 1 g. of the base. Add the calculated amount of sodium 
nitrite required to diazotize the sulphanilic acid; and, after 
cooling the mixture, pour into it the calculated amount of 
hydrochloric acid (1 mol). Dissolve the equivalent amount of 
dimethylaniline in a little hydrochloric acid and add it to the 
diazonium solution just prepared. When the mixture is made 
alkaline by the addition of sodium hydroxide, the azo-salt will 
separate at once. Collect the precipitate mon a filter and re- 
crystallize it from hot water. 

a. To a hot solution of the sodium salt, add dilute acetic 
acid. 

b. To a hot solution of the salt, add an excess of concentrated 
hydrochloric acid. How do you explain the different results 
obtained in a and 6? (Cf. Hantzsch, Ber. 41, 1187 (1908); 
Stieglitz, J. Am. Chem. Soc. 25, 112 (1903).) 

c. Reduction of Helianthine. Dissolve 3 g. of stannous 
chloride (SnCl.,2 H.O) in 6 c¢.c. of concentrated hydrochloric 
acid. Make a hot concentrated solution of helianthine (1 g.), 
and add the stannous chloride solution to it, until the color is 
entirely removed. When the mixture is cooled and stirred, 
sulphanilic acid will separate. What is the other reduction 
product? 

Benzidine Dyes. 

118. Benzoblue. (Disazo-dye.) Dissolve 2.3 g. of benzidine 
in 7 g. of hydrochloric acid (sp. gr. 1.18) and 125 c.c. of water. 
Diazotize this solution, cooled by ice, by adding 1.7 g. of sodium 
nitrite dissolved in 10 c.c. of water. Pour the solution into 
an alkaline solution of 1,8-amino-naphthol 3,6-disulphonic acid 


100 DIAZONIUM SALTS, ETC. [§ 119 


(“H acid”). The dye will separate in brilliant needles. This 
dye will color wool without a mordant. 

a. What is Congo red? Trypan blue? 

119. Polyazo-dye. Dissolve this benzoblue in slight excess 
of hydrochloric acid, and add to it the calculated amount of a 
sodium nitrite (.08 g. of nitrite for 1 g. of benzoblue). A deep 
greenish-blue diazonium compound will be formed. If this 
solution is poured into an alkaline solution of resorcinol, a dye 
will be formed which will color cotton green without a mordant. 
What is the meaning of the term substantive dye? adjective dye? 








CHAPTER XXII. 


PHENYLHYDRAZINE. NITROSAMINES. NITROSOPHENOL. 
DIPHENYLAMINE DYES. 


120. Phenylhydrazine by the Reduction of a Diazonium 
Compound. Dissolve 10 g. of aniline in 100 c.c. of concen- 
trated hydrochloric acid. Cool the solution thoroughly by 
surrounding it with ice, and diazotize it by adding the calcu- 
lated amount of sodium nitrite. Pour the solution slowly into 
a cold solution containing 60 g. of stannous chloride (SnCl, 2 H:O) 
dissolved in concentrated hydrochloric acid. The hydrochloride 
of phenylhydrazine will be precipitated. 

After a short time, collect the crystals and drain them thor- 
oughly. This can be done best by means of a Biichner funnel 
and a pump. Treat the crystals with a slight excess of a solu- 
tion of sodium hydroxide, and extract the liberated hydrazine 
by means of ether. When the ether solution has been dried 
(12 hours) over solid potassium hydroxide, separate the solid 
and remove the ether by distillation. Distill the phenylhydra- 
zine in vacuo. Cf. Fig.17. An oil-bath or a metal-bath must 
be used to get a temperature high enough. At 12 mm., phenyl- 
hydrazine will boil when the temperature of the bath lies be- 
tween 120°-140°. 

a. What is the action of Fehling’s solution upon phenyl- 
hydrazine? 

6. Compare the process of reduction of benzene diazonium 
- chloride in an alkaline solution of stannous chloride, with the 
process of reduction used above in the preparation of phenyl- 
hydrazine. 

121. Para-nitrosodimethylaniline and its Hydrochloride. 
Mix 5 g. of dimethylaniline with 10.5 c.c. of concentrated hydro- 
chloric acid, and add to it some crushed ice (15 g.). Dissolve 
3.2 g. of sodium nitrite in 10 c.c. of water, and add this solution 
gradually to the cold solution of the dimethylaniline salt. The 
hydrochloride of p-nitrosodimethylaniline will separate. Allow 

101 


102 PHENYLHYDRAZINE, ETC. [§ 124 


the mixture to stand twenty minutes; then collect the salt upon 
a Biichner funnel, wash it with alcohol and ether, and recrys- 
tallize it, using 12 parts of dilute hydrochloric acid (1:1). It 
must not be heated above 60° during the process of solution. 
Its melting-point is 177°. 

To prepare the free nitroso-compound, suspend a part of the 
salt in water, and add a 10 per cent. solution of sodium carbonate 
until the yellow salt is decomposed. Extract the green nitroso- 
compound with a small amount of ether. Remove most of the 
ether by distillation, pour the remaining concentrated solution 
into an Erlenmeyer flask, and allow the solvent to evaporate 
until crystals of the nitroso-compound have separated. The 
melting-point is 77°. | 

a. Reduce a portion of the nitroso-compound, using a hydro- 
chloric acid solution of stannous chloride as the reducing agent. 

b. To another portion of the nitroso-compound, add a few 
drops of a solution of potassium permanganate. What is pre- 
cipitated? How could you identify it? 

c. Compare the behavior of dimethylaniline, a tertiary aro- 
matic amine, towards nitrous acid, with the behavior of aniline, 
a primary amine, and methyl aniline, a secondary aromatic 
amine, towards the same reagent. Have nitroso-derivatives 
resembling nitroso-dimethylaniline in form been obtained from 
primary and secondary amines? [RI]. 

Diphenylamine Dyes and Related Dyes. 

122. Indoanilines. To a solution of phenol or of resorcinol in 
sodium hydroxide, add a small amount of nitroso-dimethylaniline. 
Shake the mixture with zinc dust until the color is removed. 
Filter the solution, and shake it with air. Explain the changes 
observed. Substitute a-naphthol for phenol, and repeat the 
experiment. 

123. Indamines. ‘‘ Toluylene Blue.’? Mix a water solution 
of nitroso-dimethylaniline hydrochloride with a small amount of 
meta-toluylendiamine. To one portion, add sodium hydroxide; 
to a second portion, add an excess of hydrochloric acid. 

124. Thiazine Dye. Methylene Blue. To a solution of 
p-nitrosodimethylaniline hydrochloride, add a few drops of 
ammonium sulphide and warm the solution gently. What is 
formed by the action of the sulphide? After a few seconds, add 
an excess of dilute hydrochloric acid and a few drops of ferric 








§ 126] PHENYLHYDRAZINE, ETC. 103 


chloride. Methylene blue will result. What is the formula of 
methylene blue? What relation does it bear to the indoanilines? 

125. Safranine Dye. Mauve. (First Commercial Aniline 
Dye; Perkin, 1856.) Heat 1 g. of commercial aniline containing 
toluidine with a small excess of hydrochloric acid. To the 
clear solution, add a few cubic centimeters of a dilute solution 
of potassium dichromate. 

126. Para-nitrosophenol, Quinone Monoxime. Heat a so- 
lution containing 25 g. of sodium hydroxide solution (sp. gr. 1.25) 
and 225 c.c. of water in a round-bottomed flask connected with 
a condenser and a receiver containing dilute hydrochloric acid. 
The end of the condenser-tube should just touch the surface 
of the acid in the receiver. To this solution, add small portions 
of p-nitrosodimethylaniline until 5 g. have been added. After 
the addition of each portion, close the flask, and allow the nitroso- 
compound to dissolve before a fresh sample is introduced. 
When all of the nitroso-compound has been used, boil the mix- 
ture until the dark-green color changes to a reddish-yellow tint. 

Cool the alkaline product, acidify it with sulphuric acid, and 
extract it with ether. When the ether has been distilled, nitroso- 
phenol will be left as a brown crystalline solid. Separate it, 
and dry it. It decomposes with a slight explosion at 120°-130°. 

If the hydrochloric acid in the receiver is evaporated on a 
water-bath, dimethylammonium chloride will be obtained. 

a. Liebermann’s ‘‘Nitroso’’ Reaction. Dissolve a few crys- 
tals of nitrosophenol (quinone monoxime) in an excess of phenol, 
and warm this mixture with concentrated sulphuric acid. A blue 
color will appear, which will change to red when the product is 
poured into water. 


CHAPTER XXIII. 
PHENOLS AND SOME RELATED COMPOUNDS. 


127. Phenol by the Diazo-reaction. 

Pour 10 g. of aniline into 300 c.c. of water, and add gradually 
8 c.c. of concentrated sulphuric acid. With this solution, cooled 
to 40°-50°, mix a solution of sodium nitrite containing the 
calculated amount necessary to diazotize the aniline salt. Heat 
this solution for 30 minutes on a water-bath at a temperature 
varying from 40°-50°. When a current of steam is passed into 
this liquid, phenol will distill, Add sodium chloride to the 
distillate, and extract the phenol by means of ether. Dry the 
ether extract, and subject the solution to fractional distillation. 
Phenol boils at 183°. 

a. Treat a small amount of phenol with a strong solution of 
sodium hydroxide. What do you observe? Acidify the alkaline 
solution. What is the result? 

b. Dissolve a drop of phenol in water, and add bromine water 
to it as long as the bromine is readily absorbed. Collect the 
precipitate upon a filter, dry it on a piece of porous plate, and 
determine its melting-point. This compound, 2,4,6-tribrom- 
phenol, is frequently used in detecting the presence of and in 
determining the quantity of phenol. 

c. Phenol from Benzene Sulphonic Acid. Fuse 1 g. of 
sodium hydroxide in a small porcelain crucible, and add 0.5 g. 
of sodium benzene sulphonate. Cf. §98. Continue the heating 
for five minutes, but avoid a temperature high enough to cause 
the fused mass to char. Cool the product and dissolve it in 
water. After making the solution acid by means of hydrochloric 
acid, filter it, and notice the odor of the filtrate. (?) Add 
bromine water in slight excess to the filtrate. Collect the 
precipitate, wash it, dry it, and determine its melting-point. 
(Cf. test b above.) 

d. To a dilute solution of phenol, add a few drops of a dilute 
solution of ferric chloride. 

104 








§ 129] PHENOLS AND RELATED COMPOUNDS 105 


e. Make dilute solutions of pyrocatechin and of resorcinol, 
and test each with ferric chloride. To the pyrocatechin solu- 
tion containing ferric chloride, add some sodium carbonate. 
This change in color is characteristic of pyrocatechin. 

f. Compare the behavior of the phenols with the reactions 
of acetoacetic ethyl ester and acetylacetone in the presence of 
ferric chloride. Cf. §63 and § 87. 

128. Anisol, Phenyl Methyl Ether. Dissolve 15g. of phenol 
in 50 c.c. of water and 20 c.c. of 10 N. sodium hydroxide. Pour 
this mixture into a flask (250 ¢.c.) and add slowly 25 c.c. of 
dimethyl sulphate (commercial). Dimethyl sulphate is odor- 
less, but extremely poisonous. Be careful not to breathe the 
vapor. Perform the operation under a hood. The mixture will 
become so warm that thorough shaking and cooling of it will 
be necessary to keep the temperature between 40° and 50°, as 
shown by a thermometer placed in the mixture. At first, the 
clear liquid will become turbid; and, in the course of a few min- 
utes, a light layer of oil will float upon the surface. The re- 
action may be considered complete when the product no longer 
becomes warm spontaneously. (Cf. §75, Methyl Thiocyanate.) 

To destroy the excess of dimethyl sulphate, warm the mix- 
ture to the boiling-point, and shake it frequently. Finally, 
cool the liquid, make it slightly alkaline, and extract it with 
ether. Dry the ether solution with anhydrous potassium car- 
bonate. When the ether has been removed by distillation from 
a water-bath, distill the ether, and then the anisol. Anisol 
boils at 155°. The yield will be about 90 per cent. of the theo- 
retical amount. 

a. In what sense may anisol be considered as an ester? 

\ 129. Phenyl Benzoate. After mixing 0.5 g. of phenol with 
5 c.c. water, add to it 0.8 g. of benzoyl chloride and enough 
sodium hydroxide solution to make the mixture slightly alkaline, 
even after it has been warmed and shaken. After the odor of 
benzoyl chloride has disappeared, cool the solution and allow 
it to stand for a short time. When the ester has solidified, 
collect it on a filter, wash it, and recrystallize it from alcohol. 
Dry the crystals, and determine the melting-point (69°). 

a. If this substance were boiled with a solution of sodium 
hydroxide, what would be formed? ‘Try the reaction. Acidify 
the alkaline solution. What is precipitated? 


106 PHENOLS AND RELATED COMPOUNDS [§ 130 


' 430. Ortho- and Para-nitrophenol. Dilute 27 c.c. of con- 
centrated nitric acid with 70 c.c. of water and cool the mixture 
in a stream of water. To this dilute acid, add 20 g. of phenol 
in several small portions. While the phenol is being added, 
shake the flask constantly, and keep it cool. Allow the mixture 
to stand for 12 hours. When the layer which forms has been 
separated and washed with twice its volume of water, subject 
it to distillation in a current of steam. 

The Ortho Compound. Steam will carry over the ortho- 
nitrophenol in the form of a yellow oil, which will solidify par- 
tially in the condenser-tube. Collect these crystals and dry 
them on a porous plate; they are practically pure. They may 
be very successfully recrystallized as follows: — Dissolve them in 
5 times their weight of dry ether and add 23 times their weight 
of petroleum ether. Pour this solution into an Erlenmeyer 
flask cover the flask loosely with a cap of filter-paper, and allow 
it to stand until the substance has crystallized. What is the 
principle involved in this method? 

The Para Compound. The para-nitrophenol, — which is not 
volatile with steam, — will remain in the flask as a brown tarry 
mass. In order to purify it, boil it for some time with a dilute 
(5 per cent.) solution of sodium hydroxide, and filter the dark- 
colored solution. 

Heat the filtrate with animal charcoal, and filter it again. 
When this alkaline solution has been concentrated to about 
one-third its original volume, treat it with a strong solution 
(50 per cent.) of sodium hydroxide. The sodium salt of para- 
nitrophenol will separate as the solution cools. Collect it upon 
a filter, dissolve it in the smallest amount of hot water possible, 
and precipitate it again by means of a concentrated solution of 
sodium hydroxide. (?) 

When the purified salt is suspended in water and treated with 
dilute sulphuric acid, para-nitrophenol will be formed. To 
purify it still further, recrystallize it from a small amount of 
hot water. 

a. Treat a few crystals of o-nitrophenol and of p-nitrophenol 
with a solution of sodium hydroxide. What is formed? Pass 
carbon dioxide through these solutions. Are the nitrophenols 
precipitated? Repeat the experiment, using phenol in place 
of the nitrophenols. Which is the more active acid, o-nitro- 








§ 183] PHENOLS AND RELATED COMPOUNDS 107 


phenol or phenol? Compare the hydrolysis of aniline salts and 
salts of substituted aniline derivatives with the behavior of 
these substituted phenols. Cf. Appendices D. and E. Do the 
nitrophenols decompose carbonates? 

6b. How is the fact explained that para-nitrophenol and its 
esters are colorless while its salts are colored? (Hantzsch and 
Gorke, Ber. 39, 1073, 3074.) 

ve @ 131. Picric Acid. Dissolve 0.1 g. of phenol in 2c.c. of con- 
‘centrated sulphuric acid. Pour this solution gradually into a 
mixture of 2 c.c. of concentrated sulphuric acid and 2 c.c. of 
concentrated nitric acid. After heating this mixture on a water- 
bath for 5-10 minutes, pour it into about 70 c.c. of cold water. 
When the product is cool, collect the precipitate upon a filter, 
and wash it with a mixture of 2 c.c. of water and 0.5 c.c. of 
concentrated hydrochloric acid. (?) Recrystallize the picric 
acid, using for this purpose a boiling mixture of 4 ¢c.c. of water 
and 1 ¢.c. of concentrated hydrochloric acid. When the precipi- 
tate has separated from the cool solution, collect it, and wash it 
with dilute hydrochloricacid as before. The melting-point is 122°. 

a. Is picric acid a more active acid than phenol? Does it 
decompose carbonates? 

b. How is picric acid employed as an explosive? as a dye? 
~ 132. Para-amidophenetole from Phenacetin. Boil 5 g. of 
commercial phenacetin with 10 c.c. of concentrated hydrochloric 
acid and 10 c.c. of water. A few pieces of porous plate placed 
in the flask will prevent “‘bumping.’’ The hydrolysis will be 
complete in 20-30 minutes. When the solution has cooled, the 
odor of acetic acid will be noticeable, and the hydrochloride of 
para-amidophenetole will separate. Cf. §108, Acetanilid. The 
hydrochloride melts at 234°. 

Para-amidophenetole may be made from this salt as follows: — 
Dissolve one-half of the salt in water, and add a 10 per cent. 
solution of sodium hydroxide to it until the solution reacts 
distinctly alkaline. Separate the oil which forms, and extract 
the alkaline solution by means of ether. After drying the ether 
over potassium hydroxide, remove it, and distill the para-amido- 
phenetole. The boiling-point is 142°. 

a. Treat a water solution of it with ferric chloride. 

133. Dulcin, p-Phenetole urea. Dissolve 2g. of the hydro- 
chloride of p-amidophenetole in 10 c.c. of water, and mix this 


108 PHENOLS AND RELATED COMPOUNDS [§ 133 


solution with a concentrated solution of 1.2 g. of potassium 
cyanate. The liquid will become filled with crystals of the 
urea. Collect the crystals upon a funnel, and recrystallize 
them from alcohol. Dulcin is about as sweet as cane-sugar. 
It is powsonous. 

a. In what respect does this reaction resemble the reaction 
involved in the preparation of urea from potassium cyanate and 
ammonium salts? 








CHAPTER XXIV. 


ALDEHYDES AND KETONES. 


_ Aldehydes. 
~~ 184. Benzaldehyde. 

a. Shake several drops of benzaldehyde with a concentrated 
solution of sodium hydrogen sulphite. Collect the crystals upon 
a filter-paper, dry them, and heat them with a solution of sodium 
carbonate. Cf. §28, Acetone. 

b. Mix benzaldehyde with a solution of phenylhydrazine 
in 50 per cent. acetic acid. What is formed? Cf. § 28, 
Acetone. | 

c. Does benzaldehyde reduce an ammoniacal solution of silver 
nitrate? 

d. Rub a small amount of benzaldehyde on a watch-crystal, 
and allow it to stand exposed to air for some time. What change 
has taken place? 

e. Make a dilute solution of potassium iodide containing 
starch emulsion (cf. §92, Starch Iodide). Add a drop of benz- 
aldehyde to it. Shake the mixture frequently, and allow it to 
stand in the sunlight. What are oxidases? 

135. Meta-nitrobenzaldehyde. Mix 100 c.c. of concentrated 
sulphuric acid and 8.5 c.c. of fuming nitric acid. Cool this 
acid to 0° in a freezing-mixture of ice and salt, and allow 25 g. 
of commercial benzaldehyde to flow into the acid very slowly, 
while the mixture is being stirred. During this stage, the tem- 
perature should not exceed +5°. Pour this product into a 
flask, and heat it slowly upon a water-bath until the temperature 
reaches 40°. 

Cool the product, and pour it slowly upon some crushed ice. 
Collect the m-nitrobenzaldehyde upon a Biichner funnel; dry it, 
and recrystallize it from a mixture of benzene and ligroine. Its 
melting-point is 58°. 

a. How do you explain the fact that benzaldehyde is oxidized 
on exposure to air, but is not readily oxidized by concentrated 
nitric acid at low temperature (+5°). Cf. §134, d and e. 

109 


- 


110 ALDEHYDES AND KETONES [§ 137 


136. Meta-chlorbenzaldehyde. Mix 20g. of meta-nitrobenz- 
aldehyde with a solution containing 90 g. of crystallized 
stannous chloride and 125 g. of fuming hydrochloric acid. The 
temperature may increase to such an extent that external cool- 
ing will be necessary. When the aldehyde has passed into 
solution, dilute the acid with water, and add sufficient ice to 
lower the temperature to 0°. ‘ 

While you shake this mixture, pour into it, very slowly, a 
solution of 9.2 g. of sodium nitrite dissolved in 35 c.c. of water. 
Prepare a solution of cuprous chloride by boiling 6 g. of crystal- 
lized cupric chloride and 3 g. of copper turnings with 25 c.c. 
of hydrochloric acid and 6 ¢.c. of water. When this solution 
has been cooled to about 0°, pour the diazonium solution into 
it. (Cf. Sandmeyer’s reaction.) 

After 24 hours, distill the m-chlorbenzaldehyde with steam; 
separate the oil, and dry it with calcium chloride. Subject it 
to fractional distillation, and collect the fraction which boils 
between 210° and 216°. When this fraction is cooled in a freez- 
ing-mixture, it will yield solid m-chlorbenzaldehyde. The solid 
may be freed from oil by means of a Biichner funnel and a 
pump. It boils at 213°-214°; its melting-point is 17°-18°. 

137. Stereoisomeric Aldoximes. 

Meta-chlor-a-benzaldoxime. Dissolve 10 g. of m-chlorbenz- 
aldehyde and 6 g. of hydroxylamine hydrochloride in 200 c.c. of 
water. Heat this mixture in a flask placed upon a water-bath. 
Pass a stream of carbon dioxide into the flask. (?) After sev- 
eral hours, cool the solution, and collect the crystalline oxime 
upon a filter. Recrystallize it from 95 per cent. alcohol. It 
melts at 70°-71°. It is also called meta-chlor-anti-benzald- 
oxime. 

Conversion into Meta-chlor-B-benzaldoxime. Dissolve 5 g. 
of the oxime in 50 c.c. of dry ether, and conduct into it a 
stream of dry hydrogen chloride gas. (Cf. Appendix G.) The 
hydrochloride of the oxime will finally separate as a white cry- 
stalline solid. Collect this salt upon a filter protected as much 
as possible from moist air. Wash the salt with absolute ether, 
and dry it in a vacuum-desiccator over sulphuric acid. 

To prepare the B-oxime itself, mix 5 g. of this hydrochloride 
with a solution of 2.5 g. of sodium carbonate in 25 ¢.c. of water. 
A colorless oil will form at first; after it is shaken, it will solidify. 








§ 139] ALDEHYDES AND KETONES 111 


Recrystallize the B-oxime from dilute alcohol. It is also called 
the syn-oxime. This solid will melt at 115°-116°; but, at the 
same time, it will be converted into the a-oxime. The fused 
substance, when it has solidified once more, will be found to 
melt at 70°-71°, instead of 115°-116°. , 

a. What is the significance of the terms syn and anti (a and 
8) as applied to aldoximes? How are space configurations 
chosen for two geometrical isomeres? 

Ketones. 

138. Benzophenone. Friedel and Crafts’ Reaction. In a 
1-liter flask, mix 15 g. of anhydrous aluminium chloride with 
50 c.c. of dry carbon disulphide. Through the stopper of this 
flask, pass a dropping-funnel and a bent adapter connected with 
a long condenser. At the upper end of this condenser, insert a 
calcium chloride tube bent downward and containing calcium 
chloride. From this tube there should be a long glass tube 
which reaches into a bottle and ends just above the surface of 
some water placed in the bottle. Into the dropping-funnel, 
pour a mixture of 15 g. of benzoyl chloride and 15 g. of dry 
benzene, and allow it to flow into the flask gradually. Heat 
the flask in a water-bath for two or three hours, or until the 
evolution of hydrogen chloride has practically ceased. 

Remove the carbon disulphide by distillation in the usual 
-way, and pour the residue into ice water. After adding 10 c.c. 
of concentrated hydrochloric acid, conduct steam into the 
product, and collect the distillate. Extract the ketone by means 
of ether, wash the ether with a solution of sodium hydroxide, 
and dry it. When the solvent has been removed subject the 
ketone to distillation. Use a small flask with a long side neck 
joined near the bulb, and without condenser attached to it. 
Benzophenone boils at 360°. Its melting-point is 48°. . 

139. Benzophenoneoxime. Dissolve 5 g. of benzophenone 
and 6 g. of hydroxylamine hydrochloride in 65 c.c. of alcohol and 
40 c.c. of water. Add 10 g. of sodium hydroxide dissolved 
in 15 c.c. of water, and boil the mixture for about an hour in a 
flask attached to a reflux-condenser. Dilute the product with 
a large volume of water, and acidify it with dilute sulphuric acid. 
After several hours, collect the crystalline oxime, wash it with 
water, and dry it. The melting-point is 141°. The yield will 
be nearly quantitative. (Cf. §31, Acetoxime.) 


112 ALDEHYDES AND KETONES [§ 141 


Beckmann’s Rearrangement of a Ketoxime. Dissolve 3 g. 
of benzophenoneoxime in 40 c.c. of ether dried over sodium. 
In a closed weighing-bottle, weigh out 4 g. of phosphorus penta- 
chloride in the form of a fine powder, and add it in small por- 
tions to the ether solution. Remove the ether by distillation, 
and pour the residue upon ice ina mortar. Grind the solid very 
fine, collect it upon a Bichner funnel, and wash it with water. 
When the benzanilid is dry, recrystallize it from boiling alcohol. 
The melting-point should be 162°. 

a. How is this reaction employed to determine the space 
configurations of stereoisomeric ketoximes? 

140. Benzophenone Phenylhydrazone. Dissolve 1.5 c.c. of 
phenylhydrazine in 5 ¢.c. of acetic acid (30 per cent.), and add to 
this solution 1 g. of benzophenone. The hydrozone will form 
readily when the mixture is thoroughly shaken. Collect it upon 
a filter and wash it. Dissolve it in a little hot alcohol and filter 
the solution if necessary. Add water to the filtrate until it 
shows a slight turbidity; then allow the solution to cool. The 
hydrazone will separate in crystalline form. It melts at 105°. 

141. Quinones and Related Compounds. 

a. Benzoquinone, Quinone. Dissolve 10 g. of aniline in a 
mixture of 54 g. of concentrated sulphuric acid and 200 c.c. of 
water. Cool this solution to about 10°, and add 6.4 g. of finely 
powdered potassium dichromate. This salt should be introduced 
slowly in one-gram portions. The operation should require 
about 20 minutes, during which the flask must be shaken very 
frequently. When all of the dichromate has been added, allow 
the flask to stand over night; then, with the conditions the same 
as before, add 13.5 g. of powdered potassium dichromate. The 
bluish color will finally change to brown. 

Extract the solution repeatedly with ether. If an emulsion 
should form which prevents the separation of the layers, a few 
cubic centimeters of alcohol will cause the liquids to part. When 
the ether has been removed by distillation, impure quinone will 
be left. 

The further purification of quinone may be accomplished by 
subjecting it to distillation in a current of steam. Place the 
solid in a distilling-flask, and conduct into it a rapid current of 
steam. Bright yellow crystals of quinone will collect in the con- 
denser and in the receiver. It may be recrystallized from ligroin. 








§ 141] ALDEHYDES AND KETONES 113 


a. Notice the odor of quinone. 

6. Add a few crystals of quinone to an acidulated solution of 
potassium iodide. What class of chemical compounds does 
quinone resemble in this reaction? 

y. Dissolve some quinone in chloroform, and add to it a 
solution of bromine in chloroform. What does this reaction 
suggest concerning the constitutional formula of quinone? 

6. Reduction of Quinone to Hydroquinone. Dissolve 5 g. 
of quinone in 100 c.c. of commercial soditim bisulphite solution 
(40 per cent.). It may be necessary to warm the mixture 
slightly.* After cooling the reaction product, extract the solu- 
tion repeatedly with ether. When the ether has been dried 
with anhydrous sodium sulphate, and removed by distillation, 
hydroquinone will be left as a slightly colored residue. It 
may be recrystallized from a little water containing sulphurous 
acid and animal charcoal to remove the color. The melting- 
point is 169°. 

a. To an alkaline solution of hydroquinone, add an ammoni- 
acal solution of silver nitrate. 

gB. Treat a concentrated solution of hydroquinone with ferric 
chloride. Try the same reaction with a dilute solution of 
hydroquinone and an excess of ferric chloride. Heat the mix- 
ture and observe the odor. 

y. Acetyl Derivative, Hydroquinonediacetate. Suspend some 
hydroquinone in twice its weight of acetic anhydride to which 
one drop of concentrated sulphuric acid has been added. Cool 
the product, collect the solid, and wash it with water. 

6. What structure formule have been proposed for quinone? 
Discuss the bearing of reactions a, 8, and y in both a and 8, as 
evidence in support of, or in disproof of one or the other of these 
formule. 

c. Dinitroso Resorcinol, Dichinoyldioxime.{ Dissolve 5 g. of 
resorcinol in 20 c.c. of water containing 10 c.c. of concentrated 
hydrochloric acid, and 25 g. of sodium chloride. Cool the solu- 
tion thoroughly by ice, and add slowly a cold solution of sodium 
nitrite containing 6.4 g. of sodium nitrite in 25 c.c of water. 


* Note 11. — As an alternative, suspend the quinone in a little water, 
and pass a rapid stream of sulphur dioxide into it until the solution be- 
comes almost colorless. 

} Hantzsch, Ber. 39, 162. 


114 ALDEHYDES AND KETONES [§ 141 


After one hour, collect the precipitate, wash it with a little cold 
water, and dry it. Cf. § 126, Nitrosophenol. This compound 
is known as resorcin green or fast green, and is employed with 
iron salts as mordants to color cotton green; wool may be dyed 

green by it without a mordant. | 








CHAPTER XXV. 
AROMATIC ACIDS AND THEIR DERIVATIVES. 


J 142. Benzoic Acid by the Oxidation of Benzaldehyde. 
- Heat a few drops of benzaldehyde with an aqueous solution 
of potassium permanganate. What is the precipitate formed? 
When the odor of benzaldehyde has disappeared, add a few 
drops of alcohol to decompose any excess of permanganate. 
Filter the liquid An acidify the filtrate. Benzoic acid will be 
precipitated. 

a. Are the processes usually employed in making benzoyl 
chloride, benzamide, benzoic ethyl ester similar in form to those 
which were used to make the corresponding derivatives of acetic 
acid? 

143. Benzoic Anhydride. Dissolve equa-molecular quanti- 
ties of benzoic acid and acetic anhydride in dry benzene, and 
boil the mixture for 6 hours. Subject the product to frac- 
tional distillation. The last fraction, which boils between 347° 
and 348°, is practically pure benzoic anhydride. The yield 
should be 80 per cent. (Kaufman and Luerbacher, Ber. 42, 
3483.) 

a. How is nitrogen pentoxide usually prepared? Is there any 
analogy between this method and the method just described? 

144. Benzoyl Peroxide.” Gradually dissolve some commercial 
sodium peroxide in a solution of sodium acetate, thoroughly 
cooled by crushed ice. Shake this solution with several drops 
of benzoyl chloride until a crystalline precipitate forms. Re- 
crystallize the solid, using alcohol as the solvent. Benzoyl per- 
oxide will be obtained. It will melt at 103°. 

a. Heat a small sample of the solid. 

b. Warm a little of it with an acidulated solution of potas- 
sium iodide. Explain your observation. Cf. § 134, Benzalde- 
hyde, e. 

* Pechman and Vanino, Ber. 27, 1511. 
115 


116 AROMATIC ACIDS [§ 147 


145. Salicylic Acid from Oil of Wintergreen. Mix 1 g. of 
oil of wintergreen (methyl salicylate) with a solution of 2.5 g. 
of sodium hydroxide in 15 ¢.c. of water. Heat this mixture in 
a flask connected with a reflux-condenser. When all the oil has 
disappeared, acidify the solution, and separate the solid by 
filtration; dry the acid, and determine its melting-point. 

a. How is salicylic acid obtained in large quantities? 

b. How could you prepare oil of wintergreen synthetically? 
Heat some salicylic acid with soda lime. Observe the odor. 
What is formed? 

c. To a dilute solution of salicylic acid, add a few drops of a 
very dilute solution of ferric chloride. What use is made of this 
reaction in detecting small amounts of salicylic acid; e.g.,in foods? 

146. Mandelic Acid Nitrile. Shake 15 g. of benzaldehyde 
with 50 c.c. of concentrated sodium hydrogen sulphite solution. 
Collect the addition product which forms, and wash it with a 
little water. Stir this substance with water enough to make a 
thick mixture, and pour into it a solution of 12-g. of potasstum 
cyanide dissolved in 15 c.c. of water. When this mixture is 
stirred, the solid will go into solution, and an oil will form. 
This oil is the nitrile; it is very unstable. 

a. Mandelic Acid from its Nitrile. Treat the nitrile with 
four times its weight of concentrated hydrochloric acid, and 
evaporate the mixture upon a water-bath until a crystalline 
film begins to form upon the surface of the liquid. When this 
solution has stood for several hours, collect the crystalline 
product, and extract the filtrate with ether to remove the re- 
mainder of the acid. Recrystallize the acid from water, or 
from benzene. Mandelic acid melts at 118°. 

147. Gallic Acid. 

a. Add a few drops of ferric chloride to a water solution of 
gallic acid. 

b: Rufigallic Acid. Moisten a small amount of gallic acid 
with concentrated sulphuric acid. Warm the acid until the 
mixture turns deep red; then pour the product into a little 
cold water. Rufigallic acid is a derivative of anthraquinone. 
Cf. Alizarin. 

c. Heat a little gallic acid in a dry test-tube. Does the 
liberated gas affect lime water? What are the chief products 
of decomposition? 








§ 148] AND THEIR DERIVATIVES 117 


148. Tannin. 

a. Treat a water solution of tannin with a few drops of ferric 
chloride. How are “iron” inks made? 

b. Soak a small piece of gelatine in cold water until it swells. 
Warm this gelatine with the water until it dissolves. Cool 
the solution and add tannin to it. What occurs? How is 
tannin employed in the tanning processes? 


CHAPTER XXVI. 
DERIVATIVES OF DIPHENYLMETHANE AND OF DIPHENYLETHANE. 


149. Tetramethyl-p-diamidodiphenylmethane. Mix 1 c.c. 
of formalin solution with 10 c.c. of water, and add 0.5 c.c. of 
dimethylaniline. Acidify the mixture with dilute sulphuric acid 
and shake it vigorously for a few minutes. When this product 
has been made slightly alkaline by means of sodium hydroxide, 
boil it in a dish until the odor of dimethylaniline is no longer 
noticeable. | Tetramethyl-p-diamidodiphenylmethane will be 
precipitated. 

Collect this precipitate upon a small filter, and wash it with 
water. Spread the filter in a small porcelain dish; moisten it 
with dilute acetic acid, and sprinkle upon it some finely powdered 
lead dioxide. A blue dye (hydrole) will result. (?) 

a. How is this reaction employed in similar cases as an in- 
termediate stage in making various triphenylmethane dyes com- 
mercially? 

150. Benzoin. ‘‘ Benzoin Condensation.’’ Dissolve 10 g. 
of benzaldehyde in 12 c.c. of alcohol, and add to it a solution of 
1g. of potassium cyanide in 10c.c. of water. Connect the flask 
with a reflux-condenser, and heat this solution for 15 minutes. 
When the liquid has cooled, benzoin will separate; it should be 
collected upon a filter, and crystallized from alcohol. It may 
be necessary to use a little animal charcoal to remove coloring 
matter. The melting-point is 134°. 

a. Does benzoin reduce Fehling’s solution? Cf. §89, Mono- 
saccharides. 

151. Benzil. Mix 5g. of benzoin with 15 c.c. of concentrated 
nitric acid (sp. gr. 1.4). Shake the mixture frequently, and heat 
it upon a water-bath until oxides of nitrogen are no longer visible 
and a sample poured into water gives a precipitate which, when 
dissolved in alcohol, will not reduce Fehling’s solution. 

If this test shows no reduction, pour the acid solution in ~ 
water, and collect the crystals upon a Biichner funnel. Re- 
crystallize the benzil from alcohol. The melting-point is 95°. 

a.. What is benzilic acid? How is it obtained from benzil? 

118 





CHAPTER XXVII. 


DERIVATIVES OF TRIPHENYLMETHANE — TRIPHENYLMETHANE 
DYES. 


Triphenylmethane Dyes. 2 

-\ 152. Malachite Green. (Leuco-base.) Mix 10 g. of di- 
methylaniline, 4 g. of benzaldehyde, and 8 g. of anhydrous zinc 
chloride, and heat the mixture in a porcelain dish over a water- 
bath. This mixture should be stirred frequently, and a little 
water should be added to prevent it from becoming too thick 
by evaporation. After several hours, transfer the product to a 
flask, and remove the unchanged dimethylaniline by steam dis- 
tillation. Cool this residue and pour away the solution of zinc 
chloride. Wash the impure leuco-base and dissolve it in hot 
absolute alcohol. Upon cooling, the leuco-base will separate 
in crystals, almost colorless. By repeated crystallization, it may 
be obtained colorless. 

—~\ 153. Malachite Green. (Dye.) Dissolve 3 g. of the leuco- 
base in 36.3 c.c. of normal hydrochloric acid, and dilute the 
solution with 275 c.c. of water. Cool this solution, and add 
2.2 g. of lead dioxide which has been suspended in 20 c.c. of 
water. This operation should require about 5 minutes. The 
mixture should be shaken for 5 minutes after all of the lead 
dioxide has been introduced. 

Filter the solution, add 3.5 g. of zine chloride, and then a 
sufficient amount of a saturated solution of salt to precipitate 
the dye so completely that a filtered sample of the mother liquor 
shows only a faint green color. Collect the dye and wash it 
with salt solution. It may be purified by dissolving it first in 
hot water, and then reprecipitating it by means of saturated salt 
solution. Finally, collect the dye, and dry it upon a piece of 
porous plate. 

a. Treat a sample of malachite green with an excess of con- 
centrated hydrochloric acid. (?) Add a large volume of water. 

6. Add asolution of sodium hydroxide to a sample of malachite 
green. (?) 

119 


120 TRIPHENYLMETHANE DYES [§ 157 


c. Treat a sample of the dye with zinc dust and hydrochloric 
acid. Explain these changes. 

154. Parafuchsine, Pararosaniline Hydrochloride. (Dye.) 
Mix 1 ¢.c. of aniline with 1 g. of p-toluidine and 3 g. of mercuric 
chloride. Heat this mixture to a temperature of 180°-200° for 
15 minutes. Extract the residue with alcohol, filter the solution, 
and evaporate it. Make a water solution of the residue, and 
acidulate it with dilute hydrochloric acid. 

a. Add concentrated hydrochloric acid to one portion of the 
solution. Explain the change in color. [RI]. 

b. Pararosaniline. (Color-base.) To a second portion of 
the solution, add ammonium hydroxide or sodium hydroxide. 
The color will be removed. Explain this reaction. 

c. Paraleucaniline. (Leuco-base.) To a third portion of 
the solution, add zinc dust, and warm the mixture. How is the 
color removed? 

155. Rosolic Acid. Heat a mixture of 2 c.c. of phenol, 
0.5 g. of oxalic acid, and 5 c.c. of concentrated sulphuric acid. 
Pour the red liquid into water, and add a slight excess of sodium 
hydroxide. The sodium salt of rosolic acid will be formed. 

Phthaleins. 

466. Phenolphthalein. Mix a small crystal of phenol with 
an equal volume of powdered phthalic anhydride. Place the 
mixture in a small test-tube, moisten the powder with one drop 
of concentrated sulphuric acid, and heat the tube for three 
minutes in a bath whose temperature is about 160°. Cool the 
residue, dissolve it in about 2 ¢.c. of water, and add 1 c.c. of a 
10 per cent. solution of sodium hydroxide. Filter the solution 
and pour the filtrate into water. 

—\ 157. Fluorescein. If resorcinol is substituted for phenol in 
preparation 156, and the other conditions are kept the same, 
fluorescein will be obtained. Notice the intense fluorescence of 
the water solution. 


<q. To some of the undiluted alkaline solution, add zinc dust, 
and shake the mixture. Filter the resulting solution and shake 
the filtrate with air. Compare azobenzol, pararosaniline, indo- 
anilines, indigo. 

\¥ 6. Eosin. Dissolve 6 g. of fluorescein in 20 c.c. of acetic 
acid, and add 4.5 g. of bromine dissolved in 18 ce.c. of acetic 
acid. When the mixture is warmed, all of the substance will 












‘A 





— 





§ 157] TRIPHENYLMETHANE DYES 121 


pass into solution. The addition of water will cause the eosin 
to separate in red crystals.* Collect this solid, dry it, and re- 
crystallize it from boiling alcohol. It will form crystals with 
one molecule of alcohol of crystallization. The yield should be 
about 8 g. 

Kosin is not soluble in water. For dyeing purposes, it is 
necessary to convert it into one of its soluble salts, usually the 
sodium salt. : 

Mix 5 g. of eosin with 0.8 g. of sodium carbonate; moisten 
the mixture with a little alcohol and add 5 c¢.c. of water. Heat 
these substances on a water-bath until the evolution of carbon 
dioxide has ceased. Then add 15 c.c. of alcohol, heat the solu- 
tion to boiling, and filter it while it is still hot. From the cold 
solution, a brown sodium salt of eosin will crystallize. 

The ammonium salt of eosin may be made as follows: — 
Spread a thin layer of eosin upon a filter-paper placed over a 
dish containing concentrated ammonia water and covered with 
a funnel. The change will be complete when a sample of the 
solid will give a clear solution in water. 


* Note 12.— Fluorescein paper — made by drying strips of paper 
which have been dipped in a solution containing 1 g. of fluorescein in 200 
parts of 50 per cent. acetic acid — is frequently used to detect traces of 
bromine. Strips of the paper are lemon-yellow in color. They will 
assume a rose-pink hue when placed in bromine vapor. 


CHAPTER XXVIII. 
EXPERIMENTS IN DYEING. 


158. Dyeing by Precipitation. 

a. Chrom Yellow. Boil 10 small strips of cheese-cloth in a 
soap solution and rinse them thoroughly with water. Prepare 
two baths, one containing a solution of lead acetate, the other 
containing a solution of potassium dichromate. Heat these 
baths until they boil, and immerse a strip of cloth first in the 
bath containing lead acetate, then in the bath of potassium 
dichromate. Can the yellow color of the cloth be removed by 
washing it with water? 

b. Indigo Dyeing. Grind 1 g. of natural indigo and 0.3 g. of 
ferrous sulphate with water in a mortar until a thin paste is 
formed. Pour this mixture into a wide-mouthed bottle (8 oz.) 
and add 0.4 g. of slaked lime. Fill the bottle with water and 
close it air-tight with a stopper. When the solution has become 
practically colorless, dip a strip of clean cheese-cloth into the 
solution and expose it to the air. Explain the reactions involved 
in this process. 

159. Direct Dyes. Substantive Dyes for Cotton. 

a. Congo Red, a Benzidine Dye. Dissolve 0.2 g. of Congo 
red in 50 c.c. of water, and add to it 0.2 g. of sodium carbonate 
dissolved in 20 c.c. of water; and 0.4 g. of sodium sulphate dis- 
solved in 20 c.c. of water. Pour this mixture into a deep porce- 
lain dish, and add 10 c.c. of water. When this bath is boiling, 
immerse strips of clean cheese-cloth in it, and continue the heat- 
ing for one or two minutes. Rinse the strips thoroughly with 
water. Is the color “fast’’? 

b. Primuline, a Thiazol Dye. Dissolve 0.2 g. of primuline 
in 300 c.c. of water which contains 1.5 g. of sodium chloride and 
0.3 g. of sodium carbonate. 


Note 13. —In dyeing operations, salts used as sodium chloride 
fn this case are often spoken of as “‘assistants’’. Cf. § 95, I, c and 
d; II, c. Are dyes in any way related to colloids? 

122 











§ 160] EXPERIMENTS IN DYEING 123 


Heat this bath and place in it three strips of clean cheese- 
cloth. Boil the bath 10 minutes. Can the color be removed 
by rinsing the cloth in water? 

160. Developing the Color on the Fiber. Ingrain Colors. 

a. Prepare the following baths: — (1) Dissolve 0.3 g. of 
sodium nitrite in 600 c.c. of cold water, and immediately before 
using the bath, add 3 c.c. of concentrated hydrochloric acid. 
(2) Dissolve 0.1 g. of sodium hydroxide in 25 c.c. of water and 
add 0.1 g. of 6-naphthol. Heat the mixture until the naphthol 
dissolves and add 175 c.c. of water. (3) Dissolve 0.1 g. of 
resorcinol in a solution of 0.2 g. of sodium hydroxide in 25 c.c. 
of water. Then dilute this solution with 175 c.c. of water. 

Place two strips of the cloth dyed in § 159, b, in the cold nitrite 
bath (1). After about 10 minutes, remove them and rinse 
them. Place one of these strips in bath (2) and the other in 
bath (3). This will develop the color. Wash the cloth with 
water and note the fastness of the color. 

b. Para-nitraniline Red. Ice Colors. Printing. Mix 5 g. 
of 6-naphthol with 5 g. of a solution of sodium hydroxide (sp. 
gr. 1.384 or 40° Baumé) and 25 c.c. of water. To this solu- 
tion add 19 g. of Turkey red oil and 200 c.c. of water. Dip 
pieces of clean cheese-cloth in this bath. Place them upon a 
plate of glass, dry them partially with filter paper, and allow 
them to dry upon the glass support. 

To make the diazo solution, dissolve 1.4 g. of p-nitraniline in 
4 c.c. of concentrated hydrochloric acid and 4 c.c. of water. 
Add 5 g. of ice, and pour into it a solution of 0.7 g. of sodium 
nitrite in 5 c.c. of water. Stir the solution vigorously and 
allow it to stand for 30 minutes in ice; then filter it into a mix- 
ture containing 50 g. of starch-tragacanth, 5 g. of ice, and 2.5 g. . 
of sodium acetate. 


Note 14. — The starch tragacanth used as thickening may be made as 
follows: — Soak 50 g. of tragacanth in 1 liter of water for 12 hours. 
Heat it upon a water bath, and add a paste made by boiling an emulsion 
of 50 g. of starch in 300 c.c. of water and 200 c.c. of dilute acetic acid. 
Press this paste through a sieve. 


If some of this thick diazo solution is placed upon the cloth 
treated with 6-naphthol, the color will be developed, and will be 
- found to be fast when the cloth is washed. To illustrate the 
process of printing, prepare a small beech-wood block, 4x4 x3 


124 EXPERIMENTS IN DYEING [§ 161 


inches, with one face planed smooth. By means of a brush 
with short bristles, coated with the thickened diazo solution, 
mark across the surface of the block first in one direction and 
then across these markings in the other direction. Carefully 
press the treated surface of the block upon a piece of prepared 
cloth placed upon a sheet of blotting paper, and strike the block 
with a hammer. When the cloth is rinsed with water, the color 
will develop. 

161. Adjective Dyes for Cotton. Mordants. Lakes. 

a. Basic Dyes. Prepare two baths, one containing 0.5 g. of 
tannic acid dissolved in 500 c.c. of water; a second contaiming 
0.2 g. of tartar emetic dissolved in 200 c.c. of water. Dissolve 
about 0.1 g. of each of the following dyes in 200 c.c. of water: 
malachite green; fuchsine; methyl violet; methylene blue. 

Boil the four baths containing the dyes, and place a strip of 
clean cheese-cloth in each one. After 5 minutes, remove the 
cloth strips and rinse them thoroughly in water. Is the color 
permanent? Heat woolen yarn and white silk in these dye 
baths, and rinse them thoroughly. Do these dyes act as sub- 
stantive dyes towards wool and silk? 

Boil the baths containing tannic acid and tartar emetic, and 
place four pieces of clean cloth first in the tannic acid bath. 
After 5 minutes, remove them and wring them. Now boil them 
for 5 minutes in the tartar emetic bath and wring them again. 
Immerse one piece in each of the boiling baths of the dyes and 
heat them 5 minutes. Can you remove the color by washing 
the strips? 

b. Acid Dyes. 

a. Alizarin. Mix lce.c. of alizarin paste, 1 g. of alizarin © 
assistant (Turkey red oil), and 2.5 c.c. of 30 per cent. acetic acid 
with 125 cece. of water. Heat the mixture to effect solution. 

Add 5 ¢.c. of this alizarin solution, mixed with 100 c.c. of 
water, to each of the following solutions: 4 ¢.c. of aluminium 
sulphate solution; 2 c.c. of a saturated solution of chromic 
acetate; 2c.c. of ferric chloride (1:10). To each solution, add 
3 ¢c.c. of normal sodium hydroxide. 

Boil 50 c.c. of the alizarin solution and 500 c.c. of water in a 
deep porcelain dish, and immerse in this bath a strip of mor- 
danted cloth prepared for alizarin dyeing. Such cloth may be 
obtained from any large dealer in chemical supplies. 








§ 161] EXPERIMENTS IN DYEING 125 


V B. Picric Acid, a Nitro-Dye. Dissolve 2-3 g. of picric acid 
in a little hot water to which a few drops of sulphuric acid have 
been added. Place in this solution a piece of white woolen 
yarn, and a piece of white silk. After heating them for 1 min- 
ute, remove them from the bath, wring them, and dry them. 
Treat a piece of cheese-cloth in the same way. Are the colors 
fast in all cases? 

To a solution of lead acetate, add an alum solution as long 
as a precipitate continues to form. After the solution has 
cleared, immerse a piece of cotton cloth in the solution, and dry 
it partially. Then place it in the hot picric acid bath for 1 
minute. Wring the cloth and dry it. Is the color fast? 

y. Resorcin Green, a Quinone Oxime Dye. ‘Try the action 
of a solution of this dye upon some white woolen yarn. Cf. 
§ 141, c, Dinitroso Resorcin. 


CHAPTER XXIX. 
NAPHTHALENE AND ANTHRACENE. 


Naphthalene. 

162. a-Nitronaphthalene. Pour 5 g. of nitric acid (sp. gr. 
1.33) upon 1 g. of naphthalene and allow the mixture to stand 
for 24 hours. Add water to dilute the acid, collect the precipi- 
tate and dry it. Pour upon it enough alcohol to moisten it, and 
add sufficient carbon disulphide to dissolve it with the exception 
of a small amount of dinitronaphthalene, which may be separated 
by filtration. Remove the solvent by distillation and recrystal- 
lize the nitro-compound from alcohol. The melting-point is 61°. 

a. How could this compound be changed into a-naphthyl- 
amine? Cf. § 105, Aniline. 

163. a- and B-Naphthol. 

a. Shake a little a-naphthol with water; add sodium hydroxide, 
and shake the mixture again. If carbon dioxide is passed into 
the alkaline solution, what will occur? 

6. How are these naphthols obtained? Does this method 
resemble the method used to prepare phenols? 

c. Martius’s Yellow. Dissolve 1 g. of a-naphthol in 4 c.c. of 
concentrated sulphuric acid and pour the mixture into 8 c.c. of 
concentrated nitric acid. 2,4-Dinitro-a-naphthol will be precipi- 
tated by the addition of water. Collect this precipitate upon 
a filter and wash it. It may be dissolved in dilute sodium 
hydroxide to give the sodium salt known as Martius’s yellow. 
Such a solution will dye a piece of woolen yarn deep yellow. 

164. B-Naphthol Methyl Ether. (Nerolin, Jara-Jara.) 

Dissolve 5 g. of 6-naphthol in a little methyl alcohol, and add 
5 g. of methyl iodide and 2.5 g. of potassium hydroxide. Heat 
this mixture in a flask attached to a reflux-condenser. When 
the reaction is complete (?) remove the alcohol by distillation, 
and extract the potassium iodide from the residue by several 
treatments with water. Recrystallize the methyl ether from 
alcohol. Its melting-point is 72°. It is employed in making 
certain perfumes. 

126 








§ 167] NAPHTHALENE AND ANTHRACENE 127 


165. 1-Monobrom-f-Naphthol. Dissolve 5 g. of 6-naphthol 
in a small amount of glacial acetic acid. To this concentrated 
solution, add the calculated amount of bromine necessary to 
form the monobromide. The bromine should be dissolved in 
an equal volume of glacial acetic acid, and should be added by 
means of a dropping-funnel while the 6-naphthol solution is 
cooled and shaken. When the product has stood a short time, 
collect the crystals of the bromide, and wash them with water 
containing acetic acid. The melting-point is 84°. 

Anthracene. 

166. Anthracene Picrate. Mix a solution of anthracene in 
glacial acetic acid with an equal amount of a solution of picric 
acid in the same solvent. Red crystals of the picric acid addition 
product will be formed. They melt at 138°. 

167. Anthraquinone. Pour 40c.c. of glacial acetic acid into 
a flask containing 5 g. of anthracene. Connect the flask with a 
reflux-condenser, and heat it in a bath of boiling water. Dis- 
solve 9 g. of chromic anhydride’ (CrO,) in a very little water, and 
add it to 13 c.c. of glacial acetic acid. Gradually pour this solu- 
tion through the condenser-tube into the flask. When the 
mixture has boiled for 5 minutes or so, pour the solution into 
water. Collect the precipitate, wash it, and dry it. It may be 
recrystallized from glacial acetic acid, or from toluene. ‘The 
melting-point is 273°. 

a. How can anthraquinone be changed into anthracene? 
What historical significance does this change have? 

b. How is alizarin made from anthraquinone? 

c. Warm a small amount of anthraquinone with zinc dust 
and sodium hydroxide. Filter the solution and shake it with 

Aira) 











DIVISION 2. HETEROCYCLIC COMPOUNDS. 


129 








CHAPTER XXX. 


HETEROCYCLIC COMPOUNDS: —- METHYL-PHENYLPYRAZOLONE, 
INDIGO, PYRIDINE; QUINOLINE. 


Heterocyclic Compounds. 

168. Methyl-phenylpyrazolone. In a large test-tube, mix 
5 g. of phenylhydrazine and 6.3 g. of freshly distilled aceto- 
acetic ethyl ester. Cool the mixture during the first part of the 
process. After several hours, separate the water which has 
formed, and heat the oily condensation product (?) for two 
hours upon a water-bath. To remove foreign coloring matter, 
pour the warm liquid into a little ether. Collect the crystals 
which separate and wash them with ether. By the slow evapora- 
tion of an alcoholic solution placed in a loosely covered Erlen- 
meyer flask, fine crystals, melting at 127°, may be obtained. 

a. To a solution of the pyrazolone derivative in boiling water, 
add ferric chloride. The blue color is caused by pyrazol blue, 
which may be extracted by means of chloroform. Delicacy, 
1: 10,000. Cf. §169, Indigo Blue. 

b. Treat some of the methyl-phenylpyrazolone with hydro- 
chloric acid. It will dissolve. To the acid solution, add sodium 
hydroxide enough to neutralize the acid; then add an excess. 
Explain these reactions. 

c. What is antipyrene? How is it obtained from methyl- 
phenylpyrazolone? 

169. Indigo. Indigo blue. 

a. Heat a little indigo carefully in a dry test-tube. What 
occurs? 

b. Dissolve a small amount of indigo in hot nitrobenzene, and 
allow it to separate. 

c. Mix 2 g. of indigo with 4 g. of powdered sodium hydroxide. 
Place this mixture in a hard-glass test-tube and subject it to 
dry distillation. Aniline will be formed. Make tests to prove 
that the distillate contains aniline. What is the origin of the 
term aniline? | 

3 131 


_— 


132 HETEROCYGLIG GOMPOUNDS t§ 172 


d. Indigo Sulphonic Acid. Indigo Carmine. Heat 0.2 g. 
of indigo with 2 c.c. of fuming sulphuric acid. Pour the cooled 
solution into water. 

e. Reduction of Indigo. Indigo White. (Cf. §158, Dyeing.) 

f. Heat a small amount of indigo or indigo sulphonic acid 
with concentrated nitric acid. Isatin is produced. 

170. Synthesis of Indigo from Ortho-nitrobenzaldehyde. 
To 1 c.c. of water containing a drop or two of acetone, add a few 
small crystals of o-nitrobenzaldehyde, and warm the liquid 
to a temperature of 50°, but not above this point. Cool the 
solution and add a few drops of a 10 per cent. solution of sodium 
hydroxide. At first the liquid will assume a yellow hue, which 
will soon become green, and finally, blue. Chloroform will 
extract the indigo. 

171. Pyridine. 

a. Make a water solution of pyridine and test it with neutral 
litmus paper. Explain the result. 

b. Add some of the clear pyridine solution to solutions of ferric 
chloride and of aluminium chloride. 

c. Mix a few drops of pyridine with an equal volume of 
methyl iodide. A solid is formed, and heat is evolved. (?) To 
what class of amines does pyridine belong? What is the com- 
pound produced by the action of methyl iodide upon pyridine? 
Cf. §85, Tetraethylammonium Bromide. 

172. Quinoline. Skraup’s Synthesis. Mix 6 g. of nitro- 
benzene, 9.5 g. of aniline, and 30 g. of dehydrated glycerol, ob- 
tained by heating glycerol in an open dish at 175°. Place the 
mixture in a round-bottomed flask (1 liter) and add 25 g. of 
concentrated sulphuric acid. Shake the flask during this process. 

Connect the flask with a reflux-condenser, and heat it over 
a wire gauze until a rapid evolution of water-vapor commences, 
when the flame should be removed at once. When the first 
violent reaction has abated, continue to boil the mixture for 
1 hour. It should then be diluted with water and distilled in 
a current of steam to remove nitrobenzene. 

Make the remaining solution distinctly alkaline, and subject it 
to distillation with steam until the quinoline and unchanged ani- 
line have collected in the receiver; add hydrochloric acid to the 
distillate to dissolve the quinoline and aniline; and treat this 
solution with an excess of sodium nitrite, which, by diazotizing 


/ 





§ 172] HETEROCYCLIC GOMPOUNDS 133 


the aniline salt, will eliminate this impurity. Boil this solution 
until the diazo-compound is entirely destroyed. (?) 

After adding sodium hydroxide in excess, distill the quinoline 
with steam, and then extract it with ether. When the ether 
has been removed as usual, dry the quinoline with solid potas- 
sium hydroxide, and distill it. The boiling-point is 237°. 

a. Dissolve one or two drops of quinoline in hydrochloric 
acid, and add a solution of hydrochlorplatinic acid. The chlor- 
platinate will form; it may be recrystallized from boiling dilute 
hydrochloric acid. 

b. Dissolve two or three drops of quinoline in dilute hydro- 
chloric acid, and add a solution of potassium dichromate. 
Quinoline dichromate will be formed. 


CHAPTER XXXI. 
METALLO-ORGANIC COMPOUNDS. 


173. Zinc Ethyl or Zinc Methyl. (Lachman, Am. Ch. J. 
24, 31 (1900).) Make an intimate mixture of 25 g. of zine dust 
and 3 g. of powdered copper oxide. After placing this mixture 
loosely in a short combustion-tube, pass a stream of dry hydro- 
gen gas over it, and heat the mixture just to dull redness for 20 
minutes. Allow the product to cool in a stream of hydrogen. 





Fig. 22. 


After placing this ‘‘zinc-copper-couple” in a small round- 
bottomed flask together with 25 g. of ethyl iodide, or of methyl 
iodide, connect the flask by means of a bent adapter with a dry 

134 | 








§ 174] METALLO-ORGANIC COMPOUNDS 135 


reflux-condenser. When the air in the apparatus has been re- 
placed by dry carbon dioxide, and access of air to the condenser 
has been prevented by a mercury valve, the mixture of iodide 
and zine should be heated on a water-bath until drops of the 
iodide cease to run back from the condenser. What gas escapes 
during this operation? 

After the condenser has been inverted, and-a suitable receiver 
has been provided, a stream of carbon dioxide, carefully dried 
over phosphorus pentoxide, should be allowed to flow through 
the entire apparatus before commencing the distillation. (Cf. 
Appendix G.) The flask may now be immersed carefully in 
an oil-bath (or metal-bath) which should be heated gradually 
while the zinc alkyl distills until it reaches a temperature of 150°; 
the temperature may be increased finally to 180°. 

The zinc alkyl may be purified by a second distillation in a 
stream of carbon dioxide. Owing to its spontaneous inflamma- 
bility, it is a dangerous substance to handle, or to keep; it is 
usually preserved in sealed glass tubes, or small flasks with 
tight cork stoppers. All operations with zinc alkyls must be 
carried out in an atmosphere of some indifferent gas. If a 
rapid stream of dry carbon dioxide is conducted into a large 
glass beaker or jar, it is possible to work with zinc alkyls at the 
bottom of such a vessel without danger. Make the following 
tests: — 

a. Allow a drop of zinc ethyl to come into contact with air. 

b. Fill a small glass bulb with the zinc alkyl (Instructions). 
Seal the stem, and place the bulb in a vessel of water; cover the 
bulb with a cylinder of water, and by pressing the rim of the 
cylinder upon the stem of the bulb, cause the stem to break. 
What is formed? What is the white insoluble substance? 

c. What are some of the applications which have been made 
of zinc alkyls in chemical synthesis? [R]. What is Grignard’s 
synthesis? What advantages does Grignard’s method have that 
are not possessed by the similar methods requiring zine alkyls? 

174. Lead Tetraphenyl.* Grignard’s Synthesis. To 70g. of 
ether, thoroughly dried over metallic sodium, add 25 g. of brom- 
benzene and 3.7 g. of metallic magnesium. Close the flask with 
a calcium chloride tube and allow it to stand 24 hours in a dish 
containing water. By this process, phenyl magnesium bromide 


* Pfeiffer and Truskier, Ber. 37, 1127. 


136 | METALLO-ORGANIC COMPOUNDS _ [§ 174 


will be formed. Cf. §15, Tertiary Butyl Alcohol. When the 
magnesium has disappeared, add 24 g. of dry, carefully pow- 
dered lead chloride. The chloride should be added in small 
portions. Allow this mixture to stand 2 days. Shake it occa- 
sionally. 

Add 200 ¢c.c. of water faintly acidulated with hydrochloric 
acid. Collect the dark precipitate upon a Biichner funnel, and 
dry it thoroughly. Place the dry solid in a flask connected 
with a reflux-condenser. Boil it with 100 c.c. of benzol, and 
filter the benzene through a folded filter, but leave the solid in 
the flask. Repeat the extraction with benzene. Combine the 
filtrates, and concentrate them until the volume is about 75 c.c. 
When this solution cools, lead tetraphenyl will separate in 
colorless needles, which melt at 222°. 


2 PbCl, + 4C;H;MgBr = Pb + Pb (C.H;), + 2 MgCl. 
+ 2 MgBr:. 








APPENDICES. 


= 


APPENDIX A. TEMPERATURE MEASUREMENT AND 
HEAT UNITS. HEAT VALUE. 


TABLE I. —Interconversion of Thermometric Readings on 
the Centigrade and Fahrenheit Scales. 


F C 


Freezing 
point 





Fig. 23. 


137 


138 


APPENDICES 


GENERAL FORMULAE. 


C. = Centigrade; F. = Fahrenheit. 
=3-t+ 32°F. 
= $- (£ — 32)°C. 


TABLE OF CENTIGRADE AND FAHRENHEIT DEGREES. 





32.0 
33.8 
39.6 
37.4 
39.2 
41.0 
42.8 
44.6 
46.4 
48.2 
50.0 
51.8 
53.6 
55.4 
57.2 
59.0 
60.8 
62.6 
64.4 
66.2 
68.0 


141.8 
143.6 
145.4 
147.2 
149.0 
150.8 
152.6 
154.4 
156.2 
158.0 
159.8 
161.6 
163.4 
165.2 
167.0 
168.8 
170.6 
172.4 
174.2 
176.0 





100 


TABLE II. — Corrections to Apply to Melting-points and 
Boiling-points for Emerging Stem and Changes in 


Pressure. 


For the determination of accurate melting-points and boiling- 
points, a standard thermometer should be used. If the thread 
of mercury is partially outside of the heated bath (melting- 
point) or of the vapor (boiling-point), a correction must be added 


APPENDICES 139 


to the observed reading in degrees. The following formula may 
be used to calculate this correction: 


Correction = N (7 —t) xX 0.000154. 


T = apparent temperature in degrees Centigrade regis- 
tered by the main thermometer. 

N =length of mercury column in degrees above the 
surface of the heated bath or vapor. 

é = temperature of a second thermometer, the bulb of 
which is placed at half the length of N above the 
surface of the bath or vapor. 

0.000154 = the apparent expansion of mercury in glass for 1° C. 


TABLE OF CORRECTIONS TO BE ADDED FOR DIFFERENT 
VALUES OF N AND T-t. 


OonPRWWNHEHOO. 
Dao WN OON DOO 


0.02 
0.03 
0.06 
0.09 
0.12 
0.15 
0.18 
0.22 
0.25 
0.28 
0.31 


Sood o.oo S'S 
SO aml ae an) as len lemon (an yam) 
NK OONOOIWNHE O 
WFR OOPN ON ON OS 
See OOCCOCcCCOO 
OIWwWNOCONO HPWH OO 
HC W 00 DD NID & = 0100 
See eS HH OOCOCOO 
CODPWR ONATOWEH © 
OID OOF NY LP ONIO CO 
NNRFKE KEK OCCOSO 
HDD OO NTR DD OO NOTIN 
ONmATN OWS BO Orb) 
WWNNNRKE HK OCS 
SIWO ODN ORR ATO 
SOW O OS 01 00 = ST 00 





_ This correction may be avoided by using a short thermometer 
the stem of which is completely immersed in the bath or vapor. 
In the determination of boiling-points, an additional correction 
must be made for variations in pressure if the boiling-points at 
760 mm. are desired. At pressures varying between 720 and 
780, this correction will be approximately 0.1° C. for every 2.7 
mm. It will have the plus (+) sign below 760 mm. and the 
minus (—) sign with higher pressures. For such slight changes 
in pressure, no correction for melting-points need be applied, 
since for such variations the correction is negligible. 


140 APPENDICES 


TABLE III. — Table of Freezing-mixtures of Snow or Powdered 
Ice and Various Substances. 


100 parts of snow at — 1° mixed with the indicated weight of the fol- 
lowing substances will give the temperature shown in the third column. 


Substance. shasta <! ent 
Potassitum sulphate ss 5:2 ¢ cen w sea 10 —1.9 
Sodium carbonate crys.: ...s...4>:.08) 20 —2.0 
PoOtAassiuTO NIUTaALe ot ea hee ee 13 —2.85 
Potassium chlorides... 3.440. ee 30 —10.9 
Ammonium chioridé?..22..0 4502. seen 25 —15.4 
Ammonium nitrate, 265.63. eee 45 —16.75 
Sodium nitrate ii ks ae: eee 50 —21.3 
Sodium: chloride :so40224) bee eee 30 —22.4 
Calcium chloride crys. (CaClz+2 HO). 143 —50 
Solid carbon dioxide and ether ........ —100 





TABLE IV. — Comparison of the Various Heat Units. 


At the present time, several different heat units are employed 
to designate quantity of heat. The following ones are most 
frequently used: — 

a. The Gram Calorie (Small Calorie), cal., is equal to the 
amount of heat absorbed by one gram of water in warming one 
degree C. This quantity, however, is not the same for all 1° 
intervals; e.g., the amount of heat necessary to warm a gram of 
water from 0° to 1° is a somewhat different value from that 
which is required to heat it from 99° to 100°. Practically, the 
calorie measured between 15° and 16° is the most convenient. 

1 gram calorie =42,720 gram centimeters (mechanical equiva- 
lent of heat). 

6. The Kilogram Calorie (Large Calorie), Cal., is the 
amount of heat required to raise the temperature of one kilo- 
gram of water 1°C. Here, again, it will be evident that this 
quantity will vary with the different unit intervals chosen. 

c. The British Thermal Unit, B.T.U., is quite generally 
employed in engineering work in America and in England. It 
may be defined as the amount of heat necessary to raise the 


APPENDICES 141 


temperature of one pound of water 1° F. Since 1 pound is equal 
to 453.6 g., and 1° F. is equivalent to 3° C., it follows that 


1 B.T.U. = 453.6 X 8 = 252 gram calories. 


Consequently 
1 Cal. = 1000 cal. = 3.97 B.T.U._ 


1 B.T.U. = 252 cal. = 0.252 Cal. 
1 cal. = 0.001 Cal. = 0.00397 B.T.U. 


Heat Value, Calorific Power, Heat of Combustion are ex- 
pressed in calories per gram or in B.T.U’s per pound of substance. 
It is evident that the unit of mass in comparing these two 
numerical values will cancel; and in consequence, one calorie 
per gram (cal.) may be read as 3 B.T.U’s per pound. Thus, 
although the absolute value of 1000 cal. in quantity of heat is 
3.97 B.T.U’s, a heat value of 1000 cal. per gram may be read 
as 1800 B.T.U’s per pound. 


APPENDIX B. PRESSURE MEASUREMENT. 
TABLE V.— Correction of Barometric Readings. 


To reduce the reading taken at room temperature (Tem- 
perature) to the corresponding height of a column of mercury 
at 0°, subtract the proper number in the second column 
(Correction) from the actual reading in millimeters. 





Tempera- : Tempera- : Tempera- 
ture. Correction. ture. Correction. Correction. 





Tempera- Tempera- Tempera- 
Pressure. ture. Pressure. ture. Pressure. 


13.5 25.1 
14.4 26.5 
15.4 28.1 
16.3 29.8 
17.4 31.8 
18.5 33.4 
19.7 35.4 
20.9 37.4 
22.2 39.6 
23.6 760.0 


et et pe 
WHE HODOOOMD”E 
WON MON AOUNAD 





142 


APPENDIX C. VOLUME AND WEIGHT RELATIONS. 
SPECIFIC GRAVITY. 


By specific gravity * of a liquid is meant its relative weight 
compared with the weight of an equal volume of pure water 
at some definite temperature. Since the density of a liquid 
varies as its temperature changes, the scale is adjusted to a 
certain temperature, usually 15°C. with water at 15° = 1. 
In some of the following tables the values are based upon 
water at 15°. In order to transpose these values to the basis 
of water at its greatest density (+ 4°), it will be necessary to 
multiply the values in such tables by 0.99916. 

Two other scales are still in use in technical work; viz., the 
Baumé and the Twaddell. 

Baume. On the Baumé hydrometer, the scale readings bear 
no direct relation to actual specific gravity. Baumé dissolved 
15 parts of pure sodium chloride in 85 parts of water at 12.5° C. 
The point to which his instrument sank in this solution was 
marked 15, while the point to which it sank when placed in pure 
water was marked 0. The distance between these two points 
was divided into 15 equal parts, and the stem was calibrated in 
divisions of this width. The divisions are called degrees. 

In the case of liquids lighter than water, the point to which 
the instrument sank in a 10 per cent. solution of sodium chloride 
solution was marked 0; while the point to which it sank in pure 
water was marked 10. The distance between these two points 
was divided into 10 equal parts, and the stem was graded in 
equal divisions through its entire length. This instrument is 
extremely unscientific in principle. Thus, since the 0 is placed 
at the bottom of the stem, the lighter the gravity of the liquid 
the greater numerically is the scale reading; e.g., a liquid read- 
ing 70 Bé. is of a less density than one of 50 Bé., which, in turn, 
is lighter than water at 10 Bé. 


* This account, slightly modified, is taken from Thorp’s “‘ Outlines of 


Industrial Chemistry.” 
143 


144 APPENDICES 


Twaddell’s Hydrometer. The spindle of Twaddell’s hydrom- 
eter is graduated from 1 to 174. The readings are direct. The 
reading of pure water at 15.5° C. is taken as 0, and each subse- 
quent rise of 0.005 in specific gravity is recorded on the scale as 
one additional division. Thus, 10 Twaddell becomes a specific 
gravity of 1.050. The divisions are spoken of as degrees. 

Interconversion of Various Scale Values. Tw. = reading 
Twaddell; Bé. = reading Baumé; Sp. gr. = Specific gravity. 


144.3 ote ; 5 
Sp. er, = eee ne. for liquids heavier than water. 15° C. 

14 Pore Tees . 
Sp. gr. = 130 + Bé. for liquids lighter than water. 17.5° C. 
Sp. gr. = 1+ (Tw. x 0.005) 15.5° C, 


TABLE VII. — Table of Specific Gravity and Percentage of 
Sodium Hydroxide in Aqueous Solutions. 


SPECIFIC GRAVITY AT 15° COMPARED WITH WATER AT 15°=1. 
(Lunge.) 





Le 
1. 
io 
i 
tS 
1; 
Le 
i: 
iy 
is 
13 
1. 
i, 
ie 
Ly 
is 
i; 
Li 
dis 
a. 
i; 
a2 
1; 
{; 
1; 





APPENDICES 145 


TABLE VIII.— Table of Specific Gravity and Percentage 
Composition of Ammonia in Aqueous Solution. 


The correction values in the fourth column hold for the tem- 
perature interval 13-17°. For example, if the specific gravity at 
13° were found to be 0.900, the specific gravity at 15° would 
be less, and would be found by subtracting 2 x 0.00057 = 0.001 
from the value observed. This would give for the specific gravity 
0.899, or an ammonia content about one-third of one per cent. 
higher. | 


SPECIFIC GRAVITY AT 15° COMPARED WITH WATER AT 15°= 1. 
(Lunge and Wiernik.) 









































1 |. con- 
ns . 
Sp. Gr.| Nie Sp. Gr| Rie | NE at | Comsetion 
a LS EE SS ce (en (| 
1.000 | 0.00] 0.0 | 0.00018 } 0.940! 15.63] 146.9 | 0.00039 
0.998 | 0.45] 4.5 | 0.00018 | 0.938] 16.22) 152.1 | 0.00040 
0.996 | 0.91) 9.1 | 0.00019 | 0.936] 16.82] 157.4 | 0.00041 
0.994 | 1.37] 13.6 | 0.00019 § 0.934] 17.42] 162.7 | 0.00041 
0.992 | 1.84] 18.2 | 0.00020 | 0.932) 18.03] 168.1 | 0.00042 
0.990 | 2.31| 22.9 | 0.00020 | 0.930) 18.64] 173.4 | 0.00042 
0.988 | 2.80] 27.7 | 0.00021 } 0.928) 19.25] 178.6 | 0.00043 
0.986 | 3.30] 32.5 | 0.00021 | 0.926] 19.87/ 184.2 | 0.00044 
0.984 | 3.80] 37.4 | 0.00022 | 0.924] 20.49] 189.3 | 0.00045 
0.982 | 4.30] 42.2 | 0.00022 | 0.922) 21.12] 194.7 | 0.00046 
0.980 | 4.80] 47.0 | 0.00023 | 0.920) 21.75] 200.1 | 0.00047 
0.978 | 5.30] 51.8 | 0.00023 | 0.918] 22.39] 205.6 | 0.00048 
0.976 | 5.80] 56.6 | 0.00024 | 0.916] 23.03] 210.9 | 0.00049 
0.974 | 6.30| 61.4 | 0.00024 | 0.914] 23.68] 216.3 | 0.00050 
0.972 | 6.80] 66.1 | 0.00025 | 0.912) 24.33] 221.9 | 0.00051 
0.970 | 7.31] 70.9 | 0.00025 | 0.910) 24.99] 227.4 | 0.00052 
0.968 | 7.82] 75.7 | 0.00026 | 0.908] 25.65] 232.9 | 0.00053 
0.966 | 8.33/ 80.5 | 0.00026 | 0.906] 26.31] 238.3 | 0.00054 
0.964 | 8.84 85.2 | 0.00027 | 0.904) 26.98] 243.9 | 0.00055 
0.962 | 9.35] 89.9 | 0.00028 | 0.902] 27.65] 249.4 | 0.00056 
0.960 | 9.91] 95.1 | 0.00029 | 0.900] 28.33] 255.0 | 0.00057 
0.958 | 10.47| 100.3 | 0.00030 | 0.898] 29.01] 260.5 | 0.00058 
0.956 | 11.03] 105.4 | 0.00031 | 0.896] 29.69] 266.0 | 0.00059 
0.954 | 11.60] 110.7 | 0.00032 | 0.894] 30.37] 271.5 | 0.00060 
0.952 | 12.17] 115.9 | 0.00033 | 0.892) 31.05] 277.0 | 0.00060 
0.950 | 13.74] 121.0 | 0.00034 | 0.890) 31.75] 282.6 | 0.00061 
0.948 | 13.31] 126.2 | 0.00035 | 0.888] 32.50] 288.6 | 0.00062 
0.946 | 13.88] 131.3 | 0.00036 } 0.886) 33.25] 294.6 | 0.00063 
0.944 | 14.46] 136.5 | 0.00037 | 0.884| 34.10) 301.4 | 0.00064 
0.942 | 15.04] 141.7 | 0.00038 | 0.882) 34.95] 308.3 | 0.00065 


146 APPENDICES 


TABLE IX. — Table of Specific Gravity and Percentage Com- 
position of Hydrochloric Acid at 15°C. Water at 4° =1. 


(Lunge and Marchlewskt.) 


seh Per cent. sere Per cent. 15° Per cent. 
HCl HCl Cl 


es by weight. 73 by weight. by weight. 
in vacuo. 





fe ee 


ja a ee ee el 
See ee ee ee ee en ee ell aes 





TABLE X. — Table of Specific Gravity and Percentage Com- 
position of Solutions of Sulphuric Acid at 15°C. Water 


bs 
at 4°= 1. (Lunge and Isler.) 





Sp. gr. 100 parts by Sp. gr. 100 parts by 
15° weight con- 15° weight con- 
4° tains per cent. 4° tains per cent. 
in vacuo. H2SOs. in vacuo. H2SOs. 


.650 72.82 
700 vp he be 3 
.750 81.56 
.800 86.90 
.810 88.30 
.820 90.05 
.830 92.10 
.834 93.05 
.840 95 .60 
.8415 97.70 
.840 99 .20 
.8385 99.95 
. 8384 100.00 


.000 0.09 
.050 7.37 
. 100 14.35 
. 150 20.91 
. 200 27 .32 
.250 33.48 
. 300 39.19 
.350 44.82 
.400 50.11 
.450 55.03 
. 900 59.70 
.550 64.26 
. 600 68.51 


1 
1 
1 
i 
1 
1 
1 
1 
1 
1 
1 
1 
1 


ee 





147 


TABLE XI.—Table of Specific Gravity and Percentage 
ee of Solutions of Nitric Acid at 15°. Water 
at 4°=1. 


APPENDICES 


(Lunge and Rey.) 


100 parts by 100 parts by 
jo" weight con- jo” weight con- 
4° tain ae cent. 4° tain per cent. 


in vacuo. HNO. in vacuo. HNO. 


Sp. gr. 
15° 


Sp. gr. 
Loe 


.400 63 .30 
415 68 .63 
.450 77 28 
.900 94.09 
.905 96.39 
.510 98.10 
515 oUF 
.920 99.67 


.000 
.050 
.100 
.150 
. 200 
.250 
. 300 
.390 


fe el ek el et et 
ee ee a ee 





TABLE XII.—Table of Specific Gravity and Percentage 
Composition of Solutions of Alcohol and Water at Vari- 
ous Temperatures. Water at 4° = 1. 

(Mendelejeff.) 


Per cent. by 
weight of 
alcohol. 


Specific gravity of alcohol-water mixtures. 


0.99988 
0.99135 
0.98493 
0.97995 
0.97566 
0.97115 
0.96540 
0.95784. 
0.94939 
0.93977 
0.92940 
0.91848 
0.90742 
0.89595 


0.88420 


0.87245 
0.86035 
0.84789 
0.83482 
0.82119 
0.80625 








0.99831 
0.98945 
0.98195 
0.97527 
0.96877 
0.96185 
0.95403 
0.94514 
0.93511 
0.92493 
0.91400 
0.90275 
0.89129 
0.87961 
0.86781 
0.85580 
0.84366 
0.83115 
0.81801 
0.80433 
0.78945 


0.99579 
0.98680 
0.97892 
0.97142 
0.96413 
0.95628 
0.94751 
0.93813 
0.92787 
0.91710 
0.90577 
0.89456 
0.88304 
0.87125 
0.85925 
0.84719 
0.83483 
0.82232 
0.80918 
0.79553 
0.78096 





148 APPENDICES 


TABLE XIII. — Table of the Solubility of Sodium Chloride 
in Water. 


100 PARTS OF WATER BY WEIGHT DISSOLVE THE GIVEN WEIGHTS. 
(De Coppet.) 











APPENDIX D. DISSOCIATION CONSTANTS OF 
ORGANIC ACIDS AND BASES. 


Ostwald’s Dilution Formula. When an electrically neutral 
molecule, A, dissociates, 


A= mA,+ NeAe+ See (1) 
it follows in accordance with the law of mass action that 
eee Ct SOs, (2) 


The same formula applies to the dissociation of electrolytes, 
if c be chosen to represent the concentration of the undissociated 
part in terms of gram molecules per liter, and c; and c; the con- 
centrations of the ions (dissociation products) in terms of gram 
ions per liter. Since the ions occur in electrically equivalent 
amounts, the following formula holds for a binary electrolyte: 


Ke= c,2. (3) 


And if a represents the degree of dissociation (part dissociated) 
determined by any of the various physical methods — e.g. 
osmotic pressure methods or the electrical conductivity method, 
—and if V represents the volume which contains one gram 
molecular weight, then it follows that 


C= ee) and 





V ci = ae (4) 
consequently, from equations (3) and (4), 
KV (1 — a) =@?, (5) 
a? 
or K = ean (6) 


In other words, the undissociated part per unit volume is pro- 
portional to the product of the concentrations of the constituent 
149 


150 APPENDICES 


ions, and the proportionality factor is called the Dissociation 
Constant or Ionization Constant. This formula, known as 
Ostwald’s dilution formula, applies rigorously only to the less 
active acids and bases. 

Furthermore, solving this equation for a, 


yah) 


Most of the constants given in the following tables are numeri- 
cally equal to 100 times the constants obtained by Ostwald’s 
dilution formula. Such values are designated by the symbol 
100 K. Ina few cases, other multiples are used. In the system 
of notation employed to designate these values, 10 stands for 
unity followed by ten ciphers; 10—!° means a decimal point fol- 
lowed by nine ciphers and unity. 


109 = au 10,000,000,000 


107° = Se 0.0000000001. 
1010 


TABLE XIV. — A Comparison of the Dissociation Constants 
of Certain Weak Acids, Organic and Inorganic. Temper- 
ature = 25°. 





Substance. Formula. K X 102, 





H.NO, 6,400,000 
H.C.H;02 180,000 
Carbonic 
Hydrogen sulphide 





Water (C+ Con: = Ky,0) 


APPENDICES Pisa 


TABLE XV.— Monobasic Fatty Acids and Some of their 
Substitution Products. Temperature = 25°. 


Substance. Formula. 100 K. 


Formic (Ostwald). H.COOH 0.02140 
Acetic (Ostwald). . CH;.COOH 0.00180 
PLOULONIC.’. ....... CH;.CH2.COOH 0.00145 
Butyric CH:3.(CH2)2,. COOH 0.00175 
Valerianic CH;.(CH2)3. COOH 0.00156 
i CH3.(CH2)4. COOH 0.00147 
CH;.(CH2)s. COOH 0.00146 


HaAtoGgen Derivatives or Acetic Acip. (OsTWALD.) 


Monochloracetic.. . CH.Cl.COOH 0.155 
Dichloracetic CHCl..COOH 5.144 
Trichloracetic..... CCl;. COOH 120.00 


A Series OF SuBsTITUTION Propucts or Acetic Acip ILLUS- 
TRATING THE EFFECT OF VARIOUS UNIVALENT SUBSTITUENTS 
UPON THE DISSOCIATION CONSTANT. (OSTWALD.) 


CH;.COOH 0.0018 
Phenylacetic CH:2(C.H;). COOH 0.00556 
Glycollic CH.(OH).COOH 0.0152 
Thioglycollic CH.(SH).COOH 0.0225 
Monobromacetic. . CH.Br.COOH 0.138 
Monochloracetic .. CH.2Cl.COOH 0.155 
i CH.(COOH).COOH 0.163 
Sulphocyanacetic.. CH2(SCN).COOH 0.265 
Cyanacetic CH.2(CN).COOH 0.370 


DERIVATIVES OF PRoPIONIC AcID SHOWING THE INFLUENCE OF 
VARIOUS SUBSTITUENTS UPON THE DISSOCIATION CONSTANT. 


Propionic CH;3.CH2.COOH 0.00145 
6-Hydroxypropionic |CH,(OH).CH:.COOH 0.00311 
CH;3.CH(OH).COOH 0.0138 
Glyceric CH.(OH).CH2(OH).COOH 0.0228 
Iodopropionic CH.ICH2.COOH 0.0090 
Trichlorlactic CCl;.CH(OH).COOH 0.465 





152 APPENDICES 


TABLE XVI. — Dibasic Acids and Some of their Substitution 
Products. (Ostwald.) Temperature = 25°. 





Substance. Formula. 


COOH.COOH 
Malonic (Walden)... CH2(COOH). 
Succinie C2H.(COOH).2 
Glutaric C3:Hs(COOH )2 
Pimelic CsHio(COOH).2 


Dipasic UNSATURATED AcIps ILLUSTRATING THE RELATION 
BETWEEN CONFIGURATION AND DISSOCIATION CONSTANTS. 


Hyproxy DrrivaTives oF Drsasic AcIps. 


Succinic C.H,.(COOH). 0.00665 
i-Malic C.H3;(OH).(COOH): 0.0399 
Tartaric (d-, l-, r-) C.H2(OH)2. (COOH). 0.097 





APPENDICES 153 


TABLE XVII. — Benzoic Acid and Some of its Substitution 
Products. (Ostwald.) Temperature = 25°. 


Substance. Formula. 100 K. 


Benzoic (Bauer) CsH;.COOH ~ 0.0073 
Cinnamic C.H;.CH =CH.COOH | 0.00355 


o-Nitrobenzoic CsH4. NO2.COOH 0.616 
p-Nitrobenzoic CsHs.NO2. COOH 0.0396 
m-Nitrobenzoic CsH4. NO2. COOH 0.0345 


m-Chlorbenzoic C.H,4.Cl. COOH 0.0155 
o-Chlorbenzoic C.H..Cl. COOH 0.0132 
p-Chlorbenzoic C.H,.Cl. COOH 0.0093 


o-Hydroxybenzoic, salicylic.| CsH..(OH).COOH 0.102 
m-Hydroxybenzoic C.H..(OH).COOH 0.0087 
p-Hydroxybenzoic C.sH,.(OH).COOH 0.0029 


Dihydroxybenzoic (2, 6)....| CesH3.(OH)2. COOH 5.00 

Dihydroxybenzoic (2, 3)....| CsH3.(OH)2,. COOH 0.114 
Dihydroxybenzoic (2, 5)....| CsH3.(OH)2. COOH 0.108 
Dihydroxybenzoic (2, 4)....| CsH3.(OH)2. COOH 0.052 





TABLE XVIII.— Phenol and Some of its Substitution 
Products. Temperature = 25°. 


Substance. Formula. 100 K. 


Phenol (Walker) C.sHs.0OH 0.000000013 


o-Nitrophenol (Bader) CeHy.NO2.0H /|0.000043 
m-Nitrophenol (Bader) CsHy.NO2.0H /|0.000012 


p-Nitrophenol (Bader) CsHi.NO2.0H  |0.0000089 


Dinitrophenol (1, 2, 6) (Bader).. .|CsH3. (NO2)2.0H 0.0174 
Dinitrophenol (1, 2, 4) (Bader).. .|CsH3.(NOz2)2-OH|0.008 

Dinitrophenol (1, 3, 6) (Bader).. .|CsH3.(NOz2)2.0H |0.0007 
Dinitrophenol (1, 2, 3) (Bader). se CsH3.(NO2)2.0H 0.0012 
Dinitrophenol (1, 3, 4) (Bader)... .|CsH3. (NOz)2.OH 0.0004 








154 APPENDICES 


TABLE XIX. — Dissociation Constants of Some Organic 
Bases. (Bredig.) Temperature = 25°. 





Substance. Formula of the Base. 





ALIPHATIC AMINES. 


Methylamine : ~ 0.050 
Ethylamine ; 0.056 
Dimethylamine : 0.074 
Diethylamine : 0.126 
Trimethylamine 0.0074 
Triethylamine 0.064 


K=1.6X10—-4 


C;-H;NH;0H K=1.1 < 10-10 
C.sH;CH.NH;0H 2.4x10-5 


o-Nitraniline (Farmer). ...| CsH4NO,.NH;0H 610-4 
m-Nitraniline CsHsaNO.NH;OH 4X 10-12 
p-Nitraniline CsHz.NO,NH;0H 1.210-3 





REFERENCE TO THE LITERATURE. 


Ostwald, Z. fur Phys. Chem., 3, 170; 31, 433. Bredig, Z. fiir Phys. Chem., 13, 289. 
Walker, Z. fiir Phys. Chem., 4, 319. Walker, Z. fiir Phys. Chem., 32, 137. 
Bader, Z. fiir Phys. Chem., 6, 289. Bauer, Z. fiir Phys. Chem., 56, 218. 
Walden, Z. fur Phys. Chem., 8, 433. . 


APPENDIX E. HYDROLYSIS OF SALTS OF WEAK 
ACIDS AND WEAK BASES. 


TABLE XX. 


Temperature = 25°. 
(From Walker’s Physical Chemistry.) 


Per cent. of 


Substance. Formula. hydrolysis. 


Salts of Weak Acids x 


Potassium phenolate 

Potassium cyanide 

Sodium tetraborate 

Sodium acetate NaC2H;302 


Hea? Weak Bases - 


10 
Aniline hydrochloride CsHsN H3.Cl 
p-Toluidine CH;C.H,N H3.Cl 
o-Toluidine CH;CsH.NH;.Cl 

NH2CONH;.Cl 

Concentration 39 
o-Nitraniline hydrochloride ..| NO.CesH,NH3.Cl 
m-Nitraniline hydrochloride. .| NO2C;H,NH3.Cl 
p-Nitraniline hydrochloride ..| NOzCsH,NH;.Cl 
Acetanilide hydrochloride... .| CsHs.N(COCHs) H2.Cl 





155 


APPENDIX F. LIST OF APPARATUS NEEDED 
TO PERFORM THE EXPERIMENTS IN 
THIS OUTLINE. 

(ORIGINAL OUTFIT.) 


RETURNABLE ARTICLES. 
1 Adapter, bent. 
2 Bottles, vial-mouthed, 1000 c.c., plain. 
4 ovr Wide 250 cau 
2 7 evaiale < 200. C.0:aie aan 
1 Bucket, small, granite ware. 
2 Bunsen burners. 
1 Calcium chloride tube, straight, 18 cm. 
1 u ? S 2oeme 
2 Clamps and attachments. 
1 Condenser, Liebig’s, 55 cm. 
1 Cork borer, set of 5 and handle. 
1 Crucible, iron, 6 cm. 
1 Crucible tongs, iron. 
1 Cylinder, grad., 100 c.c. 
1 Desiccator, Scheibler’s, 10 cm. with side tube. 
1 Dropping-tube, cf. § 16. 
if Evaporating dish, 7 cm. 
1 » 10 cm. 
1 a " 12 cm. 
1 Filter pump a attachment. 
2 Flasks, flat bottom, 30 c.c. 
4 Flasks, flat bottom, 100 c.c. 
2 4 300 c.c. 
Pe ee *: “2 500 c.c. 
1 Haak es Be LOO Ge 


1 ” ~~ round bottom, 500 c.c. 
1%, 2) filtering “20a: 

AE ee distilling, 15 c.c. 

) Ea 30 ¢.c. 
evans Ms 506.6: 
be e 150 c.c. 

1 Fractionating-column, cf. § 1. 


156 


APPENDICES 157 


RETURNABLE ARTICLES. 

2 Funnels, 65 mm. 

1 Funnel, 10 mm. 

fee Buchner, 64 cm. 

Lie 677 dropping, 60 c.c. 

Dee separatory, 250 c.c. 

4 Glass plates, 4 x 4 inches. s 

1 Mortar and pestle. 

1 Nest of beakers, 50 c.c. to 600 c.c. 

1 Pinch clamp, Mohr’s. 

3 Rings, iron, three sizes. 

1 Sand bath, sheet iron. 

1 Screw clamp. 

1 Spatula, porcelain, 10 cm. 

1 Stand, iron, small. 

1 Stand, iron, medium. 

24 Test-tubes, 160 x 15 mm. 

1 Test-tube holder. 

1 Thermometer, 360°. 

1 Thistle tube. 

1 Tripod, iron. 

1 Tube, hard glass combustion, 25 cm., cf. § 20. 

1 Watch glass, 50 mm. 

eae oo TOM, 

jd a ” 100 mm. 

1 Water bath. 

1 Set of weights, 10 mg. to 50 g. 
NON-RETURNABLE ARTICLES. 

1 Clay triangle. 

1 File, triangular. 

1 File, round. 

5 ft. Glass rod, 4 mm. 

5 ft. Glass tubing, 6 mm. 

1 Package of filter paper, 9 cm. 

1 ft. Pure gum rubber tubing, ¢ in. 

9 ft. Rubber gas tubing. 

1 Sponge. 

1 Test-tube #rush. 

1 Towel. 

1 Wire gauze. 


158 APPENDICES 


List oF SpecrAL APPARATUS USED ONLY IN ONE EXPERIMENT. 
Asbestos paper, thin, § 18. 
Bath, Wood’s metal, § 57. 
sna terayt Baa es ig 

Fractionating-column, special form, § 28. 
Galvanometer, § 22. 
Kipp’s apparatus, § 178. 
Manometer, § 120. 
Pipette, 5 c.c. grad. in 0.1 ¢.c., § 96. 
Platinum electrodes, § 22. 

4 wire, fine, § 18. 
Sodium press, § 17. 
Soxhlet extractor, § 102. 
Two-liter flask, § 57. 


APPENDIX G. SOME SPECIAL APPARATUS FOR 
PREPARING REAGENTS. 


GASES. 


a. Kipp’s Apparatus. Many gases (CO, HS, H, ete.) which 
can be prepared by the action of liquid reagents upon solids, 
may be made in small amounts for laboratory uses by means of 
a Kipp Generator. The solid in large pieces rests upon the 


Zé 


p> 
| | 





Fig. 24. Kipp’s Apparatus. 


shoulders of the middle glass compartment. The liquid reagent, 
usually water or acid, is poured into the upper glass globe, from 
which it flows to the bottom compartment, and thence to the 
solid. The upper chamber serves as a reservoir to accommodate 
the liquid which, by the pressure of gas evolved after the flow 
of gas has been stopped, is forced away from the central and 
lower compartment. The gas generated passes through the 
stop-cock to appropriate apparatus containing reagents for 
159 


160 APPENDICES 


washing it or drying it. For this purpose, it is convenient to 
use a Drechsel Wash-bottle charged either with wash liquid or 
with drying agents. Large U-tubes charged with drying or 


ey | | 


SLAM FE 


SRF ERE 
BOTA SS 


Cre 





Fig. 25. Dropping-generator. 


purifying agents are frequently desirable; e.g., calcium chloride 
or phosphorus pentoxide to remove water vapor, soda-lime to 
remove acid vapor, lead acetate on glass beads to remove hydro- 
gen sulphide. 

When considerable quantities of such gases are required, it is 


APPENDICES 161 


now customary to prepare them in large, specially constructed 
generators, or to supply them from cylinders of compressed gas 
(oxygen, hydrogen, carbon dioxide, etc.) connected with pipe 
systems. By means of a pressure reducing device at some 
central supply station, the pressure at which gases from such 
cylinders are delivered can be regulated and set as required. 

b. The Dropping-generator. A very convenient form of gas 
generator, known as the dropping-generator, devised by Mr. 
Freas* of the University of Chicago, has proved very useful in 
preparing many gases in which liquids must be added during 
the process, and must be admitted to the generator flask while 
the gas, under some pressure, is being evolved. 

The following table will illustrate some of the reactions which 
may be carried out with the dropping-generator. 


TABLE XXI.. 





Reagent used in the 
Dropping-generator. 


Reagent used in the Flask. ley 


HCl (dil.) NaHCO; 

H,.O Na2O2(oxone) 

HCl (dil.) FeS (powd.) 

HCl (dil.) Zn (dust) 

NaNOz (sat. sol.) HCI (dil.) + FeCl, (heat) 
NaNOz (sat. sol.) NH,.Cl + H:20 (heat) 
HCl (dil.) 

HCl (conc.) 

H2SO, (conc.) 

H.O 2 


i OH (abs) alcohol) | H4PO, (ap. gr. 1.73) (heat) 
Bra ted HO 





A dropping-funnel of the usual kind is modified by providing 
it with a side tube of glass which connects the space above the 
liquid in the funnel with the interior of the generator flask, thus 
equalizing the pressure at the two places while the liquid, regu- 
lated by a stop-cock, is allowed to flow into the flask. A second 
stop-cock sealed in the pressure equalizing tube must be closed 
when it becomes necessary during the operation to pour more 


* Thomas B. Freas, School Science and Mathematics, February, 1907. 


162 APPENDICES 


liquid into the funnel. The gas passes from the flask through 
the annular space between the two tubes at the bottom of the 
dropping-generator, where an exit tube conducts it to a wash- 
bottle. 

This device greatly facilitates the setting up of apparatus, 
especially for lecture demonstration, since it does away with 
the usual cumbersome connections made by 
means of three-holed stoppers. 


SOLUTIONS. 


a. The Dissolving-tube. The problem of 
making filtered solutions of difficultly soluble 
crystalline solids — such as mercuric chloride, 
copper sulphate, potassium dichromate, silver 
nitrate, etc. —is one which causes considerable 
oe inconvenience when time is an item. A simple 

y device suggested by Mr. Freas* of the Uni- 
versity of Chicago is very useful for such pur- 
poses. It permits of the making of filtered 
solutions of any desired strength up to satu- 
rated solutions. 

The weighed solid is placed on a filter-plug 
of cotton or of glass-wool in the chamber of 
the dissolving-tube. An ordinary 2-liter acid 
bottle contains the measured solvent, which 
should fill the bottle to a point sufficiently high 
to permit enough water or liquid to be drawn 
up to fill the dissolving-tube; at the same time 
sufficient water should be left in the bottle to 

Fig. 26. The cover the end of the wide tube which leads to 
Dissolving-tube. the side tube of the dropping-tube. A notch 
cut in the cork of the bottle permits air to enter. ji 

When the materials are ready, the dissolving-tube is closed 
with a rubber-stopper which fits it air-tight. By means of a 
stop-cock inserted in this stopper, air is drawn from the apparatus 
until the liquid has risen and filled the dissolving-tube to a point 
slightly above the opening of the side tube. When the stop-cock 
is closed, the denser liquid around the solid will fall to the bottom 


* Thomas B. Freas, School Science and Mathematics, February, 1907. 













iti 





APPENDICES 163 


of the bottle through the longer tube, and will thus displace pure 
solvent at the surface of the liquid in the bottle. A continuous 
flow of the liquid will begin, and will not cease until all of the 
solid has disappeared or the solution has become saturated. 

b. The Soxhlet Extractor (see page 91, Fig. 21) will be 
found very serviceable when it is desirable to make a separation 
of two or more substances by means of a limited amount of 
solvent. The mixture to be extracted is placed in an extraction 
thimble * indicated in the illustration by dotted lines. The 
solvent is poured into the flask and heated until it boils. The 
vapors pass from the flask through the wide tube to the left in 
the illustration, and are condensed in the Liebig’s condenser at 
the top. The liquid then drops upon the mixture in the thim- 
ble. When the level of the liquid in the main compartment 
reaches the level of the bend at the top of the small side tube 
at the left in the illustration, the solvent with some dissolved 
substance syphons back into the flask. This action continues 
until the mixture in the thimble is completely extracted. 


* Extraction thimbles for this purpose are made by Schleichert and 
Schill, and may be purchased through any large dealer in chemical 
supplies. 


APPENDIX H. LISTS OF GASES, LIQUIDS, AND 
SOLIDS USED AS REAGENTS FOR 
ORGANIC CHEMISTRY. 


The following lists include the reagents needed to perform 
all of the experiments included in the outline. Whenever a 
reagent is used more than ten times in the outline, that is in more 
than ten different sections, no section numbers are given in the 
lists. In all other cases the numbers of all sections in which 
each reagent is used are printed in bold type. 

The letters S.R. after a name indicate that it is not advisable 
to put that substance on the side-shelves. Such substances are 
either dangerous or costly. They may be set out for the par- 
ticular experiment, or better still, in many cases, they may be 
distributed to students at the storeroom. 

The concentrations of the solutions are given in most in- 
stances. In order that the student may be informed of the 
approximate strength of each solution he uses, the solutions have 
been made of some definite normality, usually normal (N.), 
molar, half-normal (3 N.), or tenth-normal (75 N.). In a few 
special cases, the concentrations are expressed in terms of per 
cent. The number in parentheses following the symbol desig- 
nating concentration is the weight or volume of a substance 
required with water to make one liter of the solution. Sat. = 
saturated. In the case of hydrates, the calculations are based 
upon the use of the commonest commercial hydrate. Unless 
this is the case, the formula of the substance used will be given. 

It is desirable to place on the labels of the reagent bottles 
all of the information given above. This will inform the 
student, as well as the person who makes the solution, as to 
the exact nature of the contents of each bottle. 

When the experiments to be performed have been decided 
upon, it will be possible to exclude from the list of reagents for 
the shelves all materials which are shown in the following lists 
to be required only for experiments outside of those chosen. 

164 


= ee 
> 


ae = 


APPENDICES 165 


GASES. 
SECTION. 
LE 2 Seen 
UNE 2 130, 137, 163, 173 
Chlorine. . [Sad cate 81 
Hydrogen . Re ee OH Te at or 
a chloride . Ra ee a ik Neh ee S04 197 
ts sulphide ......... Pe arte Gay ae hs RAN TOR EO 
EE OOTP gs bay kde Seed as. Cie a eae ety 108 
LiqUuIDS AND SOLUTIONS. 
(600 c.c. narrow-mouthed bottles.) 
Acetic acid, glacial...... 32, 38, 94, 108, 115, 117, 165, 166, 167 
¢" ” dilute, 6 N., » (220. C.8, of 80 per cent. FY 
” anhydride. . ; . .86, 141, 143 
” ethyl ester . iy e455 
Acetone... nee sai ois: 28, 29, 31, 32, 50, BT, 93, 170 
Acetoacetic ethyl e ester . 2. epee ’ 87, 168 
Acetylacetone .. ES CR RRO SA pee ee acaba aad 8 
Acetyl chloride. . MIR Se Sy ON rar bin a, ancien, AL LOS 
Alcohol, 95 per cent. 
Aluminium chloride, #5 molar, (7% N.)................96, 105 
44 Pe hoe eA laa tiath dees abd cod hse 9 ae 
Manon cnioride, 4N.; (213.5). .............4....¢, Ol, 161 
4 ferric sulphate, 10 per cent. .......... 65 
4 hydroxide, 6 N., (400 c.c.).... 7, 45, 74, 78 
? a com’l., 7 N. 
Amylene. . MNRONE ee Le tes, 0 og gl TY Ue 5 abla nse Dao 6 
Amyl aleohol . a eet Soe ORE eee Mien ae Gok, PER oe ee Ui | 
Amy] nitrite. . 109 
1 a 106, 108, 112, ‘115, 120, 125, 141, 154, 172 
Aniline solution, sat., 3 N. ooo, Sop aed 
]-Arabinose. . RN U8 ae EEE hic dike ip Coke eS 
Barium chloride, 7; molar, (4 N.), (24.4) ................ 96 
Benzaldehyde ............... 29, 30, 134, 135, 141, 145, 150, 152 
Benzene, benzol . BRA SiNe Sachs 97, 98, 99, 100, 138, 178 
Benzoyl! chloride. . ike .11, 60, 61, 129, 138, 143 


Brom benzene, cf. phenyl ‘bromide. — 


166 APPENDICES 


SECTION. 
Bromine, element . Re .51, 66, 157, 165 
Bromine solution, 5 per cent. in : carbon tetrachloride . 6, 97, 127 
Bromine water, sat., 3 N., (15 c.c.).. 0, 0s 88, “78, 127 
Butyl alcohol, Ra Ae pectics (0s Uneeseiamee Meee 


Calcium chloride, 7) molar, (3 N.), (21.9 cryst.) ..64, 65, 95, 96 
i hydroxide, lime-water, sat., #5 N. (2 as CaQ). 


Carbon disulphide .;..., ...:<4,./.<.0 eee 74, 76, 138, 162 
Chloroform arava. ce oe ee eee . A, 8, 45, 52, 58, 63 
Chromic acetate. Ree er SS: see re at 
Cupric sulphate, N ., (125) . eee oa ra 61, 79, 87 
Diethylamine, S.R...............2.22 eae 53 
Dimethylaniline .. Pee ..108; 113, 117, 121, 149) 152 
Dimethyl sulphate, ‘Ss. R.. ase Wee 78 128 
Ethylammonium ares go N., Ay a oo een ene 8 
Ethyl bromide. . Lee Se 
Ethyl ether, absolute ve edie e seein in a ecu) pale dll eine aga ena 
Ethyl iodide, 8.R. cece vele bled dalle 0 cle) gct Wilestan aan as 
Ethyl malonic acid, SR. . Leech nee Pete es 
Ferric chloride, N., (90). 

Ferric hydroxide, colloidal sol. ...............+.--.+--- 985 
Ferrous sulphate, 75 N. .44, 83 
Fehling’s solution. . 26, 30, 89, 90, 91, 104, “120, 150 
Formaldehyde, formaline, 40 per cent coast eee ee 22, 94, 149 
Glycerol, glycerine ..:...:...+--+c4+00 «sie hoy Gey Ogee amen 


Hydrochloric acid, C.P., conc., 13 N. 
hae “dil, ON. , (467 c.c.) 


4 Use? ro N eke ae er 96 
Hydrochlorplatinic acid, S.R., 10 per cent.. .. ..52, 53, 105, 172 
Hydrogen peroxide, 10 vol Re a 50 
Hydroxylamine pei) 10 per cent... she aE 
g-Hydroxybutyric acid, 8.R. re sin al Lee 
Iodine solution (11:5 KI: 15 ane weeee ee el, 45, 92 
FeO PE DY Cn ea ; eee 


Isopropyl] iodide, S.R. . MPI 


APPENDICES 167 


SECTION. 
CE ARMM os Gin) ig ein g's b.6 64 dp bo nid eos 
Lead acetate, N.. Ree sa ee 
Ligroine, boiling-point 40°-60° . ted ware COP SL OS 
Litmus, neutral. 
Magnesium sulphate, ee Pe een, Ee AT EO 
Mercurie chloride, sat., 4 Ga Fete Re Pe 34, 48, 82 
Methy] alcohol.. i V2: p 19, 20, 22, 34, 35, 37, 48, 101, 102, 164 
” iodide, S. R. eee oes 43, 164, 171 
MPO SOUIGION 6.2, ee ie ce hs ce eve we ev vey OL 
a, oe nalts a eds pwd wae LAG 
Sa RERC NEV OOMIUITIO Fo. yh. och hy care ice ne ep nn we wend LOS 
a-Naphthol, 10 per cent. in chloroform. ................ 88 
Pirekoruiurace, N., (145)... ..6.....--..- 62 
me cero oouc,, ©. P.,16 Ni... cn... ek ces 99, 100, 130, 131, 151 
Nitric acid, dil., 6 N., , (B82 € C.C. a 
Nitrobenzene aoe ones a1013 102, LO0bpeL (2 
Nitroethane, S.R.. of TONER Ste ree a 48 
Petroleum ether, cf. ligroine. 
Phenolphthalein sol., (1 g. + 500 c.c. se Ee cies horas 36 
Phenyl bromide, brombenzene ....... HS Le 
Phenylhydrazine.. hoes 32, 93, 139, 140, 168 
Phloroglucinol, 1 per cent. sol. . pcre 20 
Phosphoric acid, sp. gr., 1.73, 46 N.. a ieee te tp) 61 
Phosphorus trioxide, S.R.. ee eae we 
Platinic chloride, cf. hydrochlorplatinie acid. 
Potassium bromide, 3 4.N., (59.5).. rs terse .8, 97 
o oa : PVCS: fia ko een cioike yo 91, “158, 171 
7 ferrocyanide, 10 per cent. re ere 65 
ie hydrogen sulphide, 33 per ‘cent, Mra) ee 
as iodide, 3 N., (83). . EKO ET oy 9 ich x Pon 
nitrate, 4 N,, (50. aie uA 22 
‘J permanganate, iN.,, (79) . As a ‘66! 68, 97, 121, 141 
4 ae 10 per ene AG aaa to N. ie ees. 65 
Pyridine. . : a as Aes TOU EL 


Resorcinol, resorcin, 0.5 per cent. sol................... 19 


Meat 


168 APPENDICES 


Schiff’s reagent. . 
Silver nitrate, 4 (42. a 


Sodium acetate, N., (136 eryst.) 
bromide, 7. vs molar, (75 N.), (10. a 
4 carbonate, N., (53 aalivcrodca 
£: chloride, 75 molar, (ao N.), (5. 85)... 


9) 9 


”” hydrogen phosphate (NasHPO,) molar . 


sat., 6.5 N., (322))) + ED, 


SECTION. 


. .29, 30 


8,9, 22, 23, 34, 36, 43, 81, 82, 84, 134 
Soap solution, teal dv abnalce +s bt se0o 


95 


a5 121, 127, 134 


” hydrogen aoe (bisulphite, 40 per cent, AY 28, 134, 146 


¢ hydroxide, 7 to N.; (4.0) . 24 
iodide, 7's molar, te N..). 332) 


di sulphate, 75 molar, 3 + N., (82. mie 
Sulphuric acid, cone., C.P., 36 N., 
4 rene C.P., 6 N;, (167. C.C; aay 


Tollen’s ecru eee 
Toluene . xh 

Turkey-red oil 

I-Xylose 5 per cent. sol. ...... 


Zinc chloride, 4 


SOLIDS. 
(250 c.c. wide-mouthed bottles.) 
APeLSIOIGe!, «0 an ee 
Acetanilid....... 2.0.0.0) 45. 0.521 ee 
Albumin 2. oi. oe ee ee 


Alizarin-paste . 


Aluminium chloride, anhydrous, § S, R. oy ea . ; eo ‘i a 
1 8-Amino-naphthol, 3,6- mae acid, ae mene meee ss - 


Ammonium chloride. . 
$ oxalate. ... 
3 
Aniline hydrochloride 3:2... |... eee 
Anthracene ... RETR ue 
Antimonious oxide........ 
Arsenious oxide, powd... 


N., (68 cryst.).. 


sulphate... 2. 6.2.2... 


126, 127, 131, 135 


i BB a80 
.. ..98, 167 


161 


89 


105 


a 167 


85 
36 


APPENDICES — 


PENANG. 6... .. ss 
- Benzoic acid . 


Bleaching-powder, } Ib. can, S.R............. 


Caffein, S.R.. 
Bien Bde: ois 


c chloride, fused sticks. 
chloride, porous fused. 
oxide, quick-lime Sepa 


9 


9 


Cane-sugar, cf. hl 
Casein.. 
Charcoal, “animal 
Chloral hydrate... 


169 
SECTION. 
ells 
peeves 
57 


80 
7 
..2, 52, 158 


ey AS, 
108, 130 


Chromic anhydride com 7 ; 3 ; x 7 Derk! ice Re tae Ce 


Cloth, cheese-. . 

9) 
Copper turnings.. 

hte ee a ea 

SOnGO Ted... 5... se 

) 

Cotton. 

Cupric acetate .. . 
»” chloride. . 

” oxide, powd. 


” sulphate, anhydrous te Se ee ee 


” ” eo 
Cyanuric acid .. 


Dextrin....... 

Diethyl tartrate... 
Dimethyl glyoxime .. 
3,5-Dinitrobenzoic acid. . 
Diphenylamine .. .. 


Pereroreroride, ANUYCTOUS....... 2.0. 6. 2 ee eee ee eee 


Ferrous sulphate..... 


cn 1h 2 eerie 


PnCHSIMe... 6. ..c... 


d-Galactose ... 
Gallic acid... 


mordanted i in strips. Saantond bie 


Pe OSpere cc osc. e 5s. 


63 
136 


170 APPENDICES 


Gelatin. «oo be ivck web in ee aso eee 


Gelatin plates. . 


O-GIUCO8C soi vse alg ole pide eis ele 0 ove clale pt grate nae 
Ghartin. oo oN ec sl cw eC a hela ble 
Glycogen iia. eis se ea ee ce ve oa be te gern 
Gum arabic; . 2960s oe deen Ds ek 


Hydroxylamine hydrochloride, 8.R 


LOCING! 5) ee dees 
Indigo, natural....... 
Iron filwigg (5) 3 oa 


Lactose, appt pai 
Lead chloride. . 

” dioxide. . 
Litharge, lead monoxide. . 
Litmus paper. 


Magnesium turnings (Grignard)... 


Malachite green . .. 


Maleiec acid, S.R.. 6.6. cs. 0s oe ee 
Maltose, malt-sugar... ........... 
Manganese dioxide, powd. .... .. .. «5: 92: iee ee 
dzMarinose.. 2s. «ago 

Mercury, metallic... ....0, ¢..., +. 2<0eeee 
Mercuric chloride, powd. :....... 2. .203ay ae eee 
Mercurie cyanide:)\o55-.ne eee 


Meta-toluylenediamine. . 


Methylamine hydrochloride, SR. . s rs e Me ay ek 


reenter sey 
~ Methyl violet . 


Methylene blue... . ae . oa eee 


Milk-sugar, cf. Lactose. 
Monochloracetic acid... . 


Naphthalene ...... 
a-Naphthol. . 
B-Naphthol . .. 


a-Naphthylamine. . uae Ae ewes 


SECTION. 


96, 148 


..88, 91, 92 


Be a! 7, 31,197, 138 


119) 14, eee 
.. ..158, 169 
97 


90 
5 oe alae 
...149, 153 

34 


Pee 15, 102, 174 


151 


ee eee ek 

wae 113, 122, 163 

die 113, 160, 163, 164, 165 
113 


APPENDICES 171 


SECTION. 
6-Naphthylamine. . EN Bee Res en one. Sas eble 
Naphthionic acid. . fee rg pe cos ae ge at Bs 
o-Nitrobenzaldehyde, S.R.. Soe rey aren ae owen WL0 
p-Nitrophenylhydrazine, S. ita Dt ee ee ure foe 
eek aise ooo vals vee eka aie 04, 66,155 
Been mee wee. -.- SIDR SALE EIN AON aA eee REY 
Paranitraniline . eee eis oR et mo Ne LOT es LIL 
Phenacetin, com’l. 132 
Phenol, carbolic acid . 113, 122, 127, 128, 129, 130, 131, Toe 156 
m-Phenylaminediamine. . he See LG 
Phosgene in toluene, 20 per cent, . hee Peng et ht SLMS ef 
Phosphorus, red. . Pieter ahah a cr UeAO RT 

ss pentachloride, S.R.. ett en onteler Loe 
a pentoxide, S.R... ile eet pane coer EN Ue 
MCU OTIG oki s cna vcu capes vcccecescveccs 156 
Ot ee ee 
Potassium carbonate, anhydrous « se Ae .59, 128 
# cyanate. . Me Ot 72, 7, 94, 133 
g cyanide, 98 per pent. Ne 20, 94, 145, 150 
ae dichromate, granular . Seabi e be a0, on, 125, 141 
“ ferricyanide . oe SAN RE POEM Rae eT! CE LANs, 
de hydrogen tartrate . LAR ea ASE ena de 85 
id hydroxide . . a eas eee ..8, 43, 51, 54, 164 
ni iodide . 109, 111, 112, 141, 144 
3; thiocyanate (sulphocyanate). . ee 65, 75 
NN te RR os lags Gace ea Seem ies 160 
Re ee 0) ok 6 Lbs oo Neca ha tale sees oat. Led 
Resorcinol (resorcin) ........... MelIS A122 0127 peel 
Rosaniline . oe ey 
Rochelle salt, ef. sodium potassium tartrate. 
Sand. . EE ea PN ie iiad sie oe Meee 
Silk, white. . Mtr eet eS Poe. a ee, ale A eee LL 
Silver nitrate, Ea i Ree ces 49 
Soda-lime. . Ee ee Pee 40, 44 
Sodium, metallic, ‘cape @ Sateen Tk. 17, 22, 44, 48. 59 


- acetate, cryst. Ke a 109, 111, ‘112, 113) 114, 143 


172 APPENDICES 


SECTION. 
Sodium, acetate, fused . a 11, 36, 41 
acid carbonate, cf. sodium n hydrogen carbonate. 
” carbonate, anhydrous. . .. 187, 159 
” chloride, CP. 

” chloride, common salt 

fs formate. . . .04, 37, 64 

” hydrogen carbonate... io arn 

” hydroxide . ...89, 67, 101, 105, 110, 111, 117, “127, 130, 

144, 169 

”” methyl sulphate. . Soe te 

ee we Nitrite fe 47, 111, 112, 116, 118, 119, 120, 121, 127, 

136, 141, 171 

7 peroxide . cones ws 144 

” potassium tartrate .. . . .26, 84 

” sulphate, hydrate. . 98. 159 


Stannous chloride, mee Se a 


Starch. . 
Sugar (cane-sugar).. 
Sulphanilic acid. . 


Tannie acid 0... 0000 0, eee 


Tin, granular..... 
p-Toluidine.... 


Uren 32st es 
Oric avid... 2 eee 


Wood Splints °*.) 2h. e aoe 
Woolen yarn, white........:..... 


Zinc dust.. 


Zinc chloride, anhydrous Re 


......110, 117, 120, 121, 136 
..91, 92, 96, 109, 112, 134 


88, 89, 90 
117 


..148, 161 
105 
154 
..44, 77, 78, 79, 96 
80 


eee 
..115, 161, 163 


..4, 103, 122, 153, 154, 157, 173 


152 


APPENDIX I. REAGENT BOTTLES AND RE- 
AGENT SHELVES. 


Borvr.eEs. 


For liquids, 500 c.c. tincture bottles of the type represented 
in the illustration are very serviceable. The wing stoppers are 
easily held between the fingers in the usual way while the reagent 
is being poured. Such stoppers are much to be preferred to 


NITRIC 
ACID 





125 


Fig. 27. 





flat stoppers for this reason. When flat stoppers are used, they 
are placed upon the shelf or desk, and in this way are frequently 
broken or returned to the wrong bottle. 

Glass-stoppered salt-mouthed iron-mould bottles, 8 oz. (250 
c.c.), with hood tops have been found to be very convenient for 
solid reagents. The depression in the stopper facilitates the 
transferring of small amounts to tubes, flasks, etc. It has been 

173 


174 APPENDICES 


found that this form of reagent bottle induces economy in the 
use of solids. With the ordinary solid stopper it is customary 
to pour solids upon slips of paper or upon watch crystals, and 
to throw away the unused portion. 


LABELS. 


Narrow gummed labels with cations and anions, or with the 
common names, such as ethyl, methyl, cone. C.P., etc., printed 
separately, have been found to be a great convenience in labeling 
sets of reagents for various laboratories. With comparatively 
few different kinds of labels countless combinations can be made 
as required. Sets of such labels can be kept ready for use in 
small oblong pasteboard boxes arranged alphabetically. Labels 
may be made to stick firmly to glass by observing the following 
precautions: — Clean the surface of the glass very carefully with 
gasoline. Moisten the label thoroughly, and press it firmly 
against the bottle by means of a piece of blotting paper until 
all of the air spaces have been removed. If the mounted label, 
previously warmed, is quickly painted with paraffine heated 
almost to the boiling-point, and the excess of paraffine is rubbed 
off, the labels will last for years. 


REAGENT SHELVES. 


The illustration (Fig. 28) shows a type of reagent shelf which 
has been used successfully with elementary classes for a number 
of years. The dimensions of the shelves pictured are 72 in. 
high x 39 in. wide X 5 in. deep. By means of narrow (3 "in.) 
strips of wood at the sides and back, each bottle is provided with 
its own numbered compartment. These strips may be fastened 
so that all bottles, both large and small, shall set 1 inch back 
from the front of the shelf. If desired, the strips may be beveled 
in front, and may also be set back 1 inch from the edge of the 
shelf. This will leave a 1-inch margin in front of the bottles which 
will make it easy to keep the shelves clean. The bottles have 
very little free play. Asa result of this, they are always opposite 
the proper number on the shelf, and the reagent shelves as a 
whole always present an orderly appearance. 


APPENDICES 175 





Fig. 28. 


Small brass stencils will be found convenient in numbering 
the compartments. The lower shelves have been made a little 
wider than the others in order to accommodate a number of 
small stone-ware jars with covers which have been used for some 
bulky solids; e.g., copper turnings, marble, nails, sand, etc. 

A shelf of the kind illustrated above will accommodate fifty 
students working at once. 





INDEX. 





Abbreviations, 2 
Absolute alcohol, 8 
Absorption curves, 82 

plotting of, 83 
Acetal of formaldehyde, 29 
Acetaldehyde, 30, 32 

Action of, on Fehling’ S solution, 
32 


Action of Schiff’sreagent on, 33 

by the decomposition of lactic 
acid, 72 

Polymerization of, 32 

Reduction of silver nitrate by, 
32 

Resin formation with, 33 

Tollen’s reagent with, 32 

Acetamide, 45 
Action of alkalies on, 46 


Action of sulphuric acid on, 46 © 


in the preparation of methyl- 
amine, 49 

Preparation of, from acetic 
ethyl ester, 45 

Use of, in preparing acetoni- 
trile, 46 

Acetanilide, Preparation of, 94 
' Action of sodium hydroxide on, 


Action of sulphuric acid on, 94 
Acetic acid, 38 
Action of chlorine on, 71 
Action on aniline of, 94 
Anhydride of, 43 
as a solvent for bromine, 127 
Chloride of, 42 
Dissociation constant of, 151 
Ethyl] ester of, 41 
Salts of, 38 
Acetic anhydride, 43 
Action of alcohol on, 43 
Action on diethyl tartrate 
of, 73 


Acetic anhydride, action on water 
of, 43 
in the preparation of benzoic 
anhydride, 115 
to determine hydr oxy l 
groups, 43 
ether, 41 
Hydrolysis of, 41 
Use of, in preparing aceta- 
mide, 45 
Acetoacetic ethyl ester, 73 
Action of ferric salts on, 73 
Condensation of, with 
phenylhydrazine, 131 
Copper salt of, 73 
Tautomerism of, 74 
Acetone, 34 
Action of hydroxylamine on, 34 
aa of phenylhydrazine on, 
6 


Action of sodium acid sul- 
phites on, 34 
Condensation of, with benzal- 
dehyde, 34 
in the preparation of chloro- 
form, 56 
Iodoform test with, 21 
p-nitrophenyl hydrazone, 36 
Oxidation of, 34 
Preparation of, from isopropyl 
alcohol, 34 
Reduction of, 34 
Acetonitrile, Preparation of, 46 
Action of sodium hydroxide 
on, 46 
Acetoxime, 35 
Acetylacetone, 61 
Action of ferric chloride on, 61 
Copper salt of, 61 
Acetyl chloride, Preparation of, 
42 


Action of aniline on, 94 


177 


178 


Acetyl chloride, action of di- 
methyl aniline on, 94 
Action of methyl aniline on, 
94 
in the preparation of acetic 
anhydride, 43 
Reaction of, with alcohol, 42 
Reaction of, with water, 42 
Acetylene, Preparation of, 13 
Action of bromine on, 14 
Copper, 14 
Flame of, 14 
Acid splitting of acetoacetic acid, 
71 


Acrolein from glycerol, 60 
Adipic acid, Dissociation con- 
stant of, 152 
Air condenser, 19 
Albumin tests, Nature of, 81 
Alcohol acids, 72 
Alcohol, 18 
Ethyl, 8, 18, 21 
Isoamyl, 21 
Iscbutyl, 21 
Propyl, 21 
Alcoholic potash, 15 
pees of,on brom benzene, 
1 
Action of, on chloroform, 57 
Action of, on ethyl bromide, 


15 
Aldehyde. Cf. acetaldehyde 
ammonia, 30 
Aliphatic hydrocarbons, 10 
Alkyl cyanides, 66 


Amides, 45 
Amines, 48 
Aliphatic, dissociation, con- 
stants of, 154 
Aromatic, dissociation con- 


stants of, 154 
Coupling of, with diazo com- 
pounds, 97 
Aminoazobenzene, 98 
by the rearrangement of di- 
azoaminobenzene, 98 
Dyeing with, 99 
Hydrochloride of, 98 
Amino acids, 78 
Aminoacetic acid, 78 


INDEX ‘ 


Bem acid, Hydrochloride 
O ) 
Preparation of, 78 
Salts of, 78 
1,8-Amino-naphthol 3,6-disul- 
phonic acid, 99 
p-Aminophenetole, 107 
Action of ferric chloride on, 107 
Hydrochloride of, 107 
Ammonia gas, 31 
Ammoniacal silver nitrate, 26 
Ammonium ferric sulphate, 62 
hydroxide, specific gravity of 
solutions of, 145 
oxalate, 63 
Reduction of mercuric salts 
by, 63 
thiocyanate, 68 
Amy] alcohol, 18 
Amylene, Action of bromine on, 


12 
Amyl nitrite as a diazotizing 
agent, 95 


Anhydride, Acetic, 43 
Benzoic, 115 
Nitric, 115 
Phosphoric, in syntheses, 46 
as a drying agent, 134 
Aniline, Action of acids on, 92 
Ager of acetyl chloride on, 


by the distillation of indigo, 
131 


Conversion into acetanilid, 94 
Dissociation constant of, 154 
in the isonitrile reaction, 57 
in the synthesis of quinoline, 
132 
Aniline hydrochloride, 93 
Action of hydrochlorplatinic 
acid on, 93 
Conversion of, into benzene 
diazonium chloride, 95 
Degree of hydrolysis of, 95, 
1 


54 
Double salt with tin chlo- 
ride, 92 
in the rearrangement of di- 
azoaminobenzene, 98 


INDEX 


Animal charcoal to remove col- 
ored impurities, 94, 118 
Anions in the precipitation of 
colloids, 80 
Anisol, Preparation of, 105 
Anthracene, 127 
ao of toanthraquinone, 
1 
picrate, 127 
Anthraquinone, 127 
Antidiazotate of p-nitraniline, 96 
Antifebrin, 94 
Antimonious oxide in’ making 
tartar emetic, 73 
Apparatus, Care of, 1 
Lists of, 156 
Special, for making reagents, 
159 


Aqueous vapor, Tension of, 142 
1-Arabinose, 75 
Action of Fehling’s solution on, 
75 


Aromatic acids, 115 
amine salts, 93 
Hydrolysis of, 93 
compounds, 85 
Asymmetric carbon atom, 72 
Azo benzene, 90 
Preparation of, from nitro- 
benzene, 90 
Reduction of, to hydrazo- 
benzene, 91 
dyes, 95 
Azoxybenzene, 90 


Bader 154 

von Baeyer, 35 

Barometer readings, Corrections 
for, 142 

Bases, ae om ai constants of, 
15 


Bauer, 154 
Baumé hydrometer, 143 
Scale readings of, 143 
Beckmann’s rearrangement, 112 
Benzalacetone, 34 
Benzaldehyde, 109 
Action of air on, 109 
Action of ammoniacal silver 
nitrate on, 109 


179 


Benzaldehyde, action of sodium 

hydrogen sulphite on, 109 

Action of phenylhydrazine on, 
109 


Benzoin condensation of, 118 
Condensation with dimethy]l- 
aniline, 119 
Conversion into m-nitroben- 
zaldehyde, 109 
Preparation of benzoic acid 
from, 115 
Use of, in preparing dibenzyli- 
dene acetone, 34 
Use of, in preparing mandelic 
acid nitrile, 116 
Benzanilid from benzophenone- 
oxime, 111 
Benzene, 87 
Action of alkaline permanga- 
nate on, 87 
Action. of bromine on, 87 
Action of concentrated. 
phuric acid on, 87 
Conversion of, into m-dinitro- 
benzene, 90 
Conversion of, into nitroben- 
zene, 89 
Diazonium chloride, 95 
Reduction of, 95 
Solution of, 97 
Hydrocarbons, 87 
Reaction of, with benzoyl chlo- 
ride and aluminium chlo- 
ride, 111 
Sulphonic acid, 88 
Benzidine, 91 
Salts of, 91 
Rearrangement of, 91 
Use of, in making dyes, 99 
Benzil, 118 
Benzine, 88 
Benzoic acid, 115 
Dissociation 
153 
Detection of carbon and hy- 
drogen in, 10 
Preparation of, 115 
Anhydride, 115 
Benzoblue, 99 
Benzoin, Preparation of, 118 


sul- 


constant of, 


180 


Benzoin, action of Fehling’s solu- 
tion on, 118 
Benzophenone by Friedel and 
Crafts’ reaction, 111 
Oxime, 111 
Phenylhydrazone, 112 
Benzoyl chloride, 115 
Action on benzene and alu- 
minium chloride, 111 
Action on ethyl alcohol, 18 
Action on glycerol, 60 
Action on glycol, 59 
Action on phenol, 105 
Peroxide, 115 
Benzylamine, Dissociation con- 
stant of, 154 
Bismarck brown, 99 
Biuret from urea, 70 
Bleaching-powder, Action of, on 
acetone, 55 
Boiling-points, Correction of, 138 
Determination of, 17 
Boric acid, Dissociation constant 
of, 150 
Bredig, 154 
British thermal unit, 140 
Definition of, 140 
Comparison of, with other 
heat units, 141 
Brom benzene, 15, 135 
Action of alcoholic potash 
on, 15 
in Grignard’s synthesis, 135 
nitrosopropane, 48 
Bromine with acetylene, 14 
acetamide, 49 
acetoxime, 48 
benzene, 87 
ethylene, 12 
fluorescein, 120 
6-naphthol, 127 
phenol, 104 
sodium nitroethane, 47 
Biichner funnel, Use of, 
trated, 19 
Bumping, Prevention of, 6, 49, 
55 


illus- 


Butyl alcohol, Tertiary, 18, 21 
Butyric acid, Preparation of, 64 
Dissociation constant of, 151 


INDEX 


Cacodylic oxide, 39 
Caffein, Action of nitric acid on, 
70 


Calcium carbide, 13 
chloride as a drying agent, 16 
malonate, 64 
oxalate, 62, 63 
oxide, 8, 16 
tartrate, 72 
Calorie, Definition of, 140 
Calorific value, 141 
Cane-sugar, 75 
Action of Fehling’s solu- 
tion on, 76 
Hydrolysis of, 76 
Caproic acid, Dissociation con- 
stant of, 151 
Carbocyclic compounds, 85 
Carbohydrates, 75 
Molisch’s test for, 75 
Carbon, Tests for, in organic 
compounds, 10 
dioxide, 161 
disulphide, 67, 111 
Carbonic acid, Dissociation con- 
stant of, 151 
Casein, 80 
Catylitic oxidation of methy] al- 
cohol, 25 
Cellulose, Hydrolysis of, 76 
Centigrade scale, 137 
Comparison. of, with Fah- 
renheit scale, 138 
Cheese cloth in dyeing, 122 
Chloral, 33 
hydrate, 33 
m-Chlorbenzaldehyde, Prepara- 
tion of, 110 
m-Chlor-a-benzaldoxime, 110 
Stereoisomeric forms of, 110 
m-Chlor benzoic acid, Dissoci- 
ation constant of, 153 
o-Chlor benzoic acid, Dissocia- 
tion constant of, 153 
p-Chlor benzoic acid, ’ Dissocia- 
tion constant of, 153 
Chlorine, Action of, on acetic 
acid, 71 
Chloroform, 31, 50 
in isonitrile reaction, 50, 57 


INDEX 


Chloroform from acetone, 57 
Reduction of, to methane, 10 
Chlorplatinate of ammonium, 50 

of methylammonium, 50 
of phenylammonium, 93 
Chromic acetate, Lake of, with 
alizarin, 124 
anhydride as an _ oxidizing 
agent, 34, 127 
Cinnamic acid, Dissociation con- 
stant of, 153 
Cobalt salts, Detection of nickel 


in, 61 
Colloidal ferric hydroxide, 79 
Colloids, Emulsion, 80 
Suspension, 79 
Congo-red, 93, 122 
Copper acetylacetone, 61 
Copper acetylene, 13 
biuret, 70 
cyanurate, 70 
formate, 37 
glycocollate, 78 
oxide in the oxidation of or- 
ganic compounds, 10 
sulphate, anhydrous, 8 
Action of, on alkaline tar- 
trate, 73 
turnings, 76 
Correction of melting-points and 
boiling-points, 138 
Coupling to form azo-dyes, 97 
Cuprous acetylene, 14 
chloride, 14 
Making of, 14 
in Sandmeyer’s reaction, 110 


Crystallization, Purification of 


substances by, 19 
Cyanacetic acid, Dissociation 
constant of, 151 
Cyanates, 66 
Cyanhydrine reaction, 116 
Cyanic acid, 66 
from cyanuric acid, 67 
Cyanide by the action of sodium 
on nitrogen compounds, 66 
Cyanogen, 66 
Cyanogen compounds, 66 
Cyanuric acid, 67 
from urea, 70 


181 


Degree of dissociation, 150 
Desiccator, illustration, 31 
Detection of halogens in organic 
compounds, 15 
Determination of melting-points, 


Government bulletin con- 
cerning, 21 
Dextrin, 76 
Diacetyl tartaric ethyl ester, 73 
Diazoaminobenzene, 98 
Action of ammoniacal silver 
nitrate on, 98 
es of hydrochloric acid on, 
9 


Diazo-compounds, 95 
Diazonium salts, 104 
Diazotizing with amy] nitrite, 95 
with nitrous acid, 95 
Tests for completeness of, 95 
Dibasic acids, 62 
Dissociation constants of, 
151 
Unsaturated, 64 
Dissociation constants of, 
151 
Dibenzylidene acetone, 34 
Action of acids on, 34 
Dibenzalacetone. Cf. Dibenzyli- 
dene acetone, 34 
Dichinoyl! dioxime, 113 
as a dye, 125 
Dichloracetic acid, Dissociation 
constant of, 151 
Dicyanogen, see Cyanogen. 
Diethylamine, Action of ethyl 
bromide on, 50 
Diethylammonium 
Dissociation 
154 
Diethyl! ether, 22, 23, 24 
Dihydroxybenzoic acids, Disso- 
ciation constant of, 153 
Diketones, 58, 61 
Dilution formula, Ostwald’s, 149 
Dimethylamine from _ p-nitroso- 
dimethylaniline, 103 
Dimethylammonium hydroxide, 
Dissociation constant of, 
154 


hydroxide, 
constant of, 


182 


Dimethyl aniline, Action on ace- 
tyl chloride, 94 
Action of nitrous acid on, 
101 
Condensation of, with ben- 
zaldehyde, 119 
Condensation of, with for- 
maldehyde, 116 
Use of, in the preparation of 
helianthine, 99 
glyoxime, 61 
sulphate as 
agent, 67 
m-Dinitrobenzene, 90 
3,5-Dinitrobenzoic acid, 19 
Dinitronaphthalene, 126 
Dinitro-a-naphthol, 126 
Dinitrophenols, Dissociation con- 
stants of, 153 
Dinitrosoresorcinol, 113 
Diphenylamine dyes, 102 
Salts of, 93 
Hydrolysis of, 93 
Diphenylethane, Derivatives of, 
118. 
Diphenylmethane, Derivatives 
of, 118 
Direct dyes, substantive dyes, 122 
Directions for the laboratory, 1 
Disaccharides, 76 
Dissociation constants, 149 
Dissolving-tube, 162 
Distillation, Fractional, 5 
in vacuo, 58, 101 
with steam, 56 
Diureids, 69 
Disazo compounds, 99 
Double bond, von Baeyer’s re- 
agent for, 6, 65, 87. 
Drechsel wash-bottle, 160 
Drinking water, Test for nitrites 
in, 99 
Dropping-generator, 160 
Gases generated in, 160 
Dropping-tube, 22 
Dulcin, p-phenetole urea, 107 
Dyalysis of ferric chloride solu- 
tion, 79 
Dyeing by precipitation, 122 . 
Experiments in, 122 


an alkylating 


INDEX 


Ebullition-tubes, 5 
Egg albumin, 80 
Action of reagents on, 80 
Electric current, Action of, on 
colloids, 79 
Emulsion colloids, 80 
Emulsoids, 80 
Kosin, Preparation of, 120 
Ammonium salt of, 120 
Sodium salt of, 120 
Ksters of benzoic acid, 18 
of 3,5-dinitrobenzoic acid, 18 
of nitrous acid, 47 
of thiocyanic acid, 67 
of isocyanic acid, 67 - 
Ether, Acetic, 41 
Diethyl, 18 
Phenyl methyl, 105 
Ethereal salts, 18 
Ethylammonium bromide, 15 
hydroxide, Dissociation con- 
stant of, 154 
Ethyl bromide, 15 
Action of silver nitrate on, 
15 
Addition of, to diethylamine, 


50 . 
Addition of, to  triethyl- 
amine, 51 
Kthylene, its preparation from 
alcohol, 11 
Ethylene dibromide, 55 
Conversion of, into glycol, 


glycol, Action of sodium on, 58 
ester of benzoic acid, 59 
Ethyl ester of acetic acid, 41 
of acetoacetic acid, 73 
of benzoic acid, 18 
of diacetyl tartaric acid, 73 
of 3,5-dinitrobenzoic acid, 20 
of tartaric acid, 73 
Ethyl iodide, 16 
Action of light on, 16 
— of silver nitrate on, 
1 
malonic acid, 64 
mercaptan, 44 
nitrite, 47 
nitrolic acid, 45 


INDEX 


Fahrenheit scale, 138 
Fast green, 114 
Fatty acids, 137 
Fehling’s solution, Action of, on 
sugars, 75, 76 
Action of,on acetaldehyde, 32 
Preparation of, 32 
Ferric chloride, anhydrous, 29 
hydroxide, Colloidal, 79 
oxalate ions, 62 
Fibrin, Swelling of, 80, 81 
Fluorescein, 120 
Fischer, Martin H., 83 
Formaldehyde, formalin, 25, 26, 
27 


Apparatus for preparing, 26 

Condensation of, with di- 
methylaniline, 118 

im milk, 27 

Leache’s test for, 27 

Resorcinol as a test for, 26 

Formic cep as a reducing agent, 

3 


from lactic acid, 72 
from methyl alcohol by oxi- 
dation, 38 
from oxalic acid, 37 
Salts of, 37 
Fractionating-columns, 29 
Freas, Thomas B., 161, 162 
Freezing-mixtures, 140 
Friedel and Crafts’ reaction, 111 
Fuchsine, Dyeing with, 124 
Fumaric acid from maleic acid, 
64 


Dissociation 
152 
Fuming nitric acid, Action of, on 
benzaldehyde, 109 


d-Galactose, 75 
Gallic acid, 116 
Conversion of, into rufigallic 
acid, 116 
Gases, Preparation of, by the 
dropping-generator, 161 
used in the course, 165 
Gelatin plates, Swelling of, 82 
Glacial acetic acid, 39 
d-Glucose, 75 


constant of, 


183 


d-Glucose, Action of Fehling’s 
solution on, 75 
Molisch’s test applied to, 75 
Glucosazone, 77 
Glutaric acid, Dissociation con- 
stant of, 152 
Gluten, Swelling of, 80 
Glyceric acid, Dissociation con- 
stant of, 151 
Glycerol, 58 
as a bath, 20 
Action on copper salts in solu- 
tion, 60 
Action of benzoyl chloride on, 
60 


Conversion into acrolein, 60 
in the preparation of formic 
acid, 37 
Glycerin, see Glycerol 
Glycine, 78 
Glycocoll, Dissociation constant 
of, 151 
Preparation of, 78 
Glycogen, 76 
Action of Fehling’s solution 
on, 76 
Glycol, Ethylene, 58 
ester of benzoic acid, 59 
Preparation of, from ethylene 
dibromide, 58 
Gram calorie, 140 
Grignard’s synthesis, 21, 136 
Gum arabic, 76 
ape of Fehling’s solution on, 
6 


““H’’ Acid, 99 
Halogens, Test for, 10 
Halogen alkyls, 15 
acids, 71 
Dissociation constants of, 
151° 
Hantzsch, 107, 119 
Hehner’s method of detecting 
formaldehyde, 28 
Heat of combustion, 141 
Heat units, 140 
Helianthine, Preparation of, 99 
Reduction of, 99 


184 


Heptylic acid, Dissociation con- 
stant of, 151 
Heterocyclic compounds, 129 
Hofmann’s mustard-oil test, 68 
Hydrazobenzene, 91 
Action of Fehling’s solution 
on, 91 ; 
from azobenzene, 91 
Rearrangement of, to benzi- 
dine, 91 
Hydrazones, 36 
of acetone, 36 
of benzaldehyde, 109 
of benzophenone, 112 
Hydrocarbons, 10 
Acetylene, 13 
Benzene, 87 
Olefine, 11 
Paraffine, 10 
Hydrochloric acid, Specific grav- 


ity of, 146 

Hydrochlorplatinic acid with 
methylammonium — chlo- 
ride, 50 


Action of, on ammonium 
chloride, 50 
Action of, on aniline hydro- 
chloride, 93 
Action of, on quinoline hy- 
drochloride, 133 
Hydrocyanic acid, Salts of, 66 
Hydrogen, Tests for, in organic 
compounds, 10 
Hydrogen peroxide, 72 
sulphide, Preparation of, 161 
Dissociation constant of, 
150 
Hydrol dye, 118 
Hydrolysis of acetic ethyl ester, 
Al 


aniline salts, 93 
acetamide, 46 
acetanilid, 94 

aromatic amine salts, 93 
cane-sugar, 76 

cellulose, 76 
diphenylamine salts, 93 
p-nitraniline salts, 93 
nitriles, 46 


INDEX 


Hydrolysis of salts of weak acids 
and bases, 155 
soap, 39 
sodium acetate, 39 
starch, 76 
Hydrophillic colloids, 80 
Hydrophobic colloids, 79 
Hydroquinone, 113 
Diacetyl derivative of, 113 
Hydroxy acids, Dissociation con- 
stants of, 151, 152 
$-Hydroxybutyric acid, 72 
Hydroxylamine, Action of, on 
aldehydes, 110 
Action of, on ketones, 35, 111 
as a reducing agent for copper 
salts, 14 
6-Hydroxypropionic acid, Disso- 
ciation constant of, 151 


Illuminating-Gas, 12 
Unsaturated hydrocarbons in, 
12 
Indoamines, 102 
Indoanilines, 102 
Indigo, 122, 131 
blue, Reactions of, 132 
carmine, 132 
Synthesis of, from o-nitroben- 
zaldehyde, 132 
Interconversion of specific grav- 
ity readings, 144 
Invert-sugar, 76 
Action of Fehling’s solution on, 


76 
Action of phenylhydrazine on, 
(ib 
Iodine, Action on carbohydrates, 
77 


Detection of, in organic com- 
pounds, 15 
Reaction with alcohol, 16 
solution for iodoform test, 21 
Iodoform reaction applied to al- 
cohols, 21 
Preparation of, 57 
Iodopropionic acid, Dissociation 
constant of, 151 
Ionization constants, 150 


INDEX 


Iron filings as a bromine carrier, 
87 


Isocyanide reaction, 57 
Isopropyl! alcohol, 21, 34 

iodide, 48 
Isomerism, An illustration of, 40 


Jara-Jara, 126 


Kekulé’s formula for benzene, 87 
hypothesis of linkings of car- 
bon atoms, 11 
Ketones, Aliphatic, 34 
Aromatic, 111 
acids, 73 
Ketonic splitting, 74 
oe Rearrangement of, 
11 


Kilogram calorie, 140 
Kipp’s apparatus, 159 


Labels, 174 
Laboratory precautions, 1 
Lactic acid, Dissociation con- 
stant of, 151 
Action of sulphuric acid on, 72 
Lactose, milk-sugar, 76 
Law of mass action, 149 
Leache’s method of detecting 
formaldehyde, 26 
Lead acetate in dyeing, 122 
chloride in Grignard’s synthe- 
sis, 1385 
dioxide as an oxidizing agent, 
118, 119 
formate, 37 
Leuco-base of fluorescein, 119 
malachite green, 120 
pararosaniline, 120 
Levulose, fruit-sugar, 75 
Liebermann’s nitroso reaction, 
103 
Liebig’s condenser, Illustrations 
of, 5, 8, 9 
Light action on ethyl iodide, 17 
in accelerating oxidation, 63, 
109 
in causing rearrangement of 
maleic acid, 64 
in processes of substitution, 
13,41 


185 

Ligroine, Action of bromine on, 
13 

List of pada used as reagents, 
65 


solids used as reagents, 168 
Lunge, Tables by, 144, 145, 146, 
147 


Lyophobice colloids, 79 
Lyophilic colloids, 80 


Magnesium in Grignard’s syn- 
thesis, 21, 185 
to reduce azobenzene, 91 
Malachite green, 119 
Action of reagents on, 119 
Maleic acid, Action of perman- 
ganate on, 65 
Conversion of, into fumaric 
acid, 64 
Dissociation constant of, 
152 
Malic acid, Dissociation con- 
stant of, 152 
Malonic acid, Decomposition of, 
by heat, 64 
Dissociation 
151 
Preparation of, from mono- 
chloracetic acid, 64 
Maltose, malt-sugar, 76 
Mandelic acid from its nitrile, 
116 
nitrile from benzaldehyde, 
116 
Manganese dioxide, 63 
d-Mannose, 75 
Manometer, 58, 101 
Martius’s yellow, 126 
Mass action, Law of, 149 
Mauve, 103 
Melting-points, 
138 


constant of, 


Correction of, 


determinations, 20 
Menge, George, 21 
Mercaptans, 44 
Mercuric chloride as an oxidizing 
agent, 37, 63 
in fuchsine preparation, 120 
cyanide, Action of silver salts 
on, 66 


186 


Mercuric cyanide in preparation 
of cyanogen, 66 
Metallo-organic compounds, 134 
Methane from chloroform, 10 
Methylal, 29 
Action of sulphuric acid on, 30 
Methyl alcohol, 18, 25, 26 
amine solution, 49 
aniline, 94 
ammonium chloride, 50 
hydroxide, Dissociation con- 
stant of, 154 
cyanide, acetonitrile, 46 
ester of formic acid, 40 
iodide in Grignard’s reaction, 
21 


isocyanate, 67 

mustard-oil, 68 

orange, 99 

salicylate, 116 

thiocyanate, 67 

violet, Dyeing with, 124 
Methylene-amino-acetonitrile, 78 

Conversion of, into glycocoll, 78 
Methylene blue, 102 
Milk, Test for formaldehyde in, 

27 


sugar, 76 
Molar solutions with colloids, 80 
Molecular rearrangement of ma- 
leic acid, 64 
of diazoaminobenzene, 98 
Molisch’s test for carbohydrates, 


Monatomic alcohols, 18 
Monobasic fatty acids, 37 
Dissociation constants of, 
151 
1-Monobrom-6-naphthol, 127 
Monochloracetic acid, 71 
Action of silver nitrate on, 
71 
Decomposition of, by carbo- 
nates, 72 
Dissociation constants of, 
151 
Monomethylaniline, 94 
Monosaccharides, 75 
Mordants, 124 


INDEX 


Mordanted cloth, 124 
Murexid from uric acid, 70 
Mustard-oils, 68 


Naphthalene, 126 
Dinitro, 126 
a-Nitro, 126 
Naphthionic acid, Coupling of, to 
form azo-dyes, 97 
a-Naphthol as a reagent for car- 
bohydrates, 75 
in the formation of azo-dyes, 
96, 97 
Nitration of; Martius’s yellow, 


126 
B-Naphthol, Action of sodium 
hydroxide on, 126 
Coupling to form azo-dyes, 96, 


97, 98 
methyl ether, 126 
1-monobrom derivative of, 127 
a-Naphthylamine, Coupling of, 
to form azo-dyes, 97 
8-Naphthylamine, Coupling of, 
to form azo-dyes, 97 
Nef, J. U., 60 
Nerolin, see 6-Naphthol methyl 
ether, 126 
Nickeldimethylglyoxime, 61 
Nitranilines, Dissociation con- 
stants of, 154 
p-Nitraniline, Conversion of, into 
a diazo-salt, 96 
Hydrochloride of, 93 
Hydrolysis of, 98, 155 
Nitric acid, Specific gravity of 
solutions of, 147 
Nitrile, Aceto, 46 
Mandelic acid, 116 
Methylene-aminoaceto-, 78 
Nitrites, Test for, in drinking 
water, 99 
m-Nitrobenzaldehyde, 109 
Nii in synthe- 
sis of indigo, 1 
Nitrobenzene, 89 
Preparation from benzene, 89 
Reduction to azoxybenzene, 90 
to azobenzene, 90 
to aniline, 92 


INDEX 


Nitrobenzoic acids, Dissociation 
constants of, 153 
Nitroethane, Sodium salt of, 47 
Nitrogen, Test for, in organic 
compounds, 45 
compounds, 45 
pentoxide, 115 
Nitrolic acid, Ethyl, 47 
Nitroparaffines, 47 
a-Nitronaphthalene, 126 
o-Nitrophenol, 106 
p-Nitrophenol, Preparation of, 
106 


Nitrophenols, Dissociation con- 
stants of, 153 
p-Nitrophenyl-antidiazotate of 
sodium, 96 
“aa of, towards reagents, 
9 


p-Nitrophenylhydrazine, 36 
Action of, on acetone, 36 
p-Nitrosodimethylaniline, 101 


Conversion of, into dyes, 
102 
Conversion of, into p-nitroso- 
phenol, 103 


Hydrochloride of, 101 

p-Nitrosophenol, 103 

Nitroso reaction, Liebermann’s, 
103 

Nitrous acid, Dissociation con- 
stant of, 150 

Non-electrolytes and swelling of 
colloids, 82 

Note-book, 1 


Oedema, 83 
Oil bath, 134 
of wintergreen, 116 
Olefines, 10 
compared with paraffines, 12 
Osazone of d-glucose, 77 
Ostwald’s dilution formula, 149 
Oxalic acid, 62 
Action of concentrated sul- 
phuric acid on, 63 
as a reducing agent, 63 
Calcium salt of, 62 
Complex-ions of, 62 


187 


Oxalic acid, Preparation of, from 
formic acid, 62 
Dissociation constant of, 
152 
in making para-rosolic acid, 


Oxidation and reduction cell, 28 

of ethyl alcohol, 18, 30 

of anthracene to anthraqui- 
none, 127 

of acetaldehyde by silver ni- 
trate, 32 

of isopropy] alcohol to acetone, 
34 


of methyl alcohol, 25, 26, 28 
Oxime of acetone, 35 
of benzophenone, 111 
of m-chlor benzaldehyde, 110 
Oxygen, Preparation of, from 
oxone, 161 


Paraffines, 10 
Paraformaldehyde, 25, 27 
Conversion of, into methylal, 
29 
Parafuchsine, pararosaniline hy- 
drochloride, 120 
Paraleucaniline, 120 
Pararosaniline, 120 
Perkin, 103 
Peroxide, Benzoyl, 115 
Petroleum ether, 12, 87 
Action of sulphuric acid on, 87 
p-Phenetole urea, 107 
Phenol, Action of bromine on, 
104 
Action of sodium hydroxide 
on, 104 
Action of ferric chloride on, 
104 
Action of nitric acid on, 106, 
107 
popping of, to form azo-dyes, 


Conversion of, into picric acid, 
107 

Conversion of, into anisol, 105 

Conversion of, into phenyl ben- 
zoate, 105 

Dissociation constant of, 153 


188 


Phenol, Preparation of, 97, 104 
Use of, in making phenol- 
phthalein, 120 
Phenolphthalein, 39, 120 
Phenylacetic acid, Dissociation 
constant of, 151 
Phenylammonium chloride, 93 
Phenyl benzoate, 105 
m-Phenylenediamine in the prep- 
aration of Bismarck 
brown, 99 
Phenylglucosazone, 77 
Phenylhydrazine, 77, 101 
Action of Fehling’s solution 
on, 101 
Condensation with acetoacetic 
ethyl ester, 131 
Hydrochloride of, 101 
in the preparation of hydra- 
zones, 36, 112 
Preparation of, 101 
Phenyl magnesium bromide, 135 
methyl ether, 105 
Phloroglucinol, 27 
Phosgene in the preparation of 
urea, 69 
Phosphoric acid, in the prepara- 
tion of acrolein, 60 
in the preparation of ethy- 
lene, 55 
Phosphorus, red, 16 
as a chlorine carrier, 71 
pentachloride in the Beck- 
mann’s rearrangement, 
112 
pentoxide, Action of, on aceta- 
mide, 46 
trichloride, Action of, on acetic 
acid, 42 
Phthaleins, 120 
Phthalic anhydride, 120 
in the preparation of fluores- 
cein, 120 
in the preparation of phenol- 
phthalein, 120 
Picric acid, 107 
addition product with anthra- 
cene, 127 
as a dye, 125 
Piloty, 48 


INDEX 


Pimelic acid, Dissociation con- 
stant of, 152 
Platinum as a catalyzer, 25 
chloride, Action on amine 
salts, 50 
Polyatomic compounds, 53 
alcohols, 58 
Polyazo-dyes of benzidine, 99 
Polyhalogen compounds, 55 
Polymerization of acetaldehyde, 
32 
of cyanic acid, 67 
Polysaccharides, 76 
Potassium acid sulphate, 60 
carbonate, Action of, on ethy- 
lene dibromide, 58 
cyanate, 66 
Conversion of, into methyl 
isocyanate, 67 
cyanide, 66 
in synthesis of organic com- 
pounds, 64, 66, 67, 78, 118 
dichromate, 18, 30, 57, 122 
ferricoxalate, 62 
complex-ion of, 63 
ferricyanide, Complex-ion of, 
62 


phenolate, Degree of hydroly- 
sis of, 1 
permanganate, Action of, on 
benzene, 87 
Action of, upon olefines, 12 
Oxidation of benzaldehyde 
by, 115 
Oxidation of oxalic acid by, 
63 
with maleic acid, 64 
thiocyanate, 67 
Precautions for the laboratory, 4 
Precipitation of colloids, 79 
Pressure, Correction of baro- 
metric, 142 
Primary amines, 50 
Prussian blue, 45 
Prussic acid, Salts of, 66 
Dissociation constant of, 
150 
Pseudonitroles, 48 
Purpuric acid, see Murexid, 48 
Pyrazol blue, 131 


INDEX 


Pyridine, 132 
Addition of methyl iodide to, 
132 


Behavior of, towards salt solu- 
tions, 1382 
Reaction of, towards litmus, 
132 
Pyrocatechin, Action of ferric 
chloride on, 105 


Quinoline, 132 
Chlorplatinate of, 133 
Dichromate of, 183 
Hydrochloride of, 133 
Skraup’s synthesis of, 132 

Quinone, 113 
monoxime, 103 
Reactions of, 113 


Reactions of alcohols, 18 
Reagent bottles, 173 
Labeling of, 174 
Shelves for, 174 
Rearrangement, Molecular, 
Beckmann’s, 112 
Benzidine, 91 
Diazoaminobenzene to ami- 
noazobenzene, 98 
of maleic acid, 64 
of stereoisomeric aldoximes, 
110 
Recrystallization, Process of, 19 
Reflux-condenser, illustration of 
use of, 8 
Resin formation with aldehydes, 


Resorcin green, 114 
Resorcinol, Action of ferric chlo- 
ride on, 105 
Coupling of, to form azo-dyes, 
97 


in the test for formaldehyde, 26 
Rosaniline, Hydrochloride of, 33 
in making Schiff’s reagent, 


Rosolic acid, Preparation of, 120 
Rufigallic acid from gallic acid, 
116 


Saccharose, see cane-sugar, 76 
Safranine dye, 103 


189 


Salicylic acid, Action of ferric 
chloride on, 116 
Action of soda-lime on, 116 
from oil of wintergreen, 116 
Test for, in food, 116 
Salts of weak bases, Hydrolysis 
of, 155 
acids, Degree of hydroly- 
sis of, 155 
Sandmeyer’s reaction, 96, 110 
Schiff’s reagent for aldehydes, 
33, 61 
Schotten-Baumann’s reaction, 
18, 59, 60, 105, 115 
Schraube, 96 
Separatory funnel, Use of, 16 
Silver acetate, 39 
nitrate, 15, 27, 37 
Action on halogen alkyls, 15 
Skraup’s quinolin synthesis, 132 
Soap, 39 
Soda-lime, 42 
Sodium metallic, Action on alco- 
hols, 18 
Disposal of residues, 24 
use of, in drying ether, 24 
Use of, in test for nitrogen, 


acetate, Action of water on, 
39 


Degree of hydrolysis of, 155 
in the preparation of acetic 
acid, 38 
Reactions with, 18, 38, 95, 96 
acid sulphite, 34 
benzene sulphonate, 89 
carbonate in preparation of 
iodoform, 57 
chloride, Effect of solutions on 
colloids, 148 
formate, 37, 40 
hydrogen sulphite, 34 
hydroxide, Specific gravity of 
solutions of, 144 
isonitromethane, 47 
methyl sulphate, 67, 105 
p-nitrophenyl-antidiazotate, 96 
peroxide in making benzoyl 
peroxide, 115 
press for making wire, 24 ® 


190 


Sodium salt of fluorescein, 120 
formic acid, 37 
eosin, 121 
tetraborate, Degree of hydrol- 
ysis of, 155 


Tannic acid as a mordant, 124 
Tannin, 117 
Tartaric acid, 72, 73 
Calcium salt of, 73 
Complex ions of, 73 
Dissociation constant of, 
152 
Tartar emetic, 73, 124 
Tautomerism, Cases of, 47, 61, 
66, 73, 103 
Tension of aqueous vapor, Table 
of, 142 
Tertiary butyl alcohol, 21 
Tetraethylammonium bromide, 
51 


Tetramethy]l- p2-diaminodiphen- 
ylmethane, 118 
Thermometer readings, 137 
scales, 1387 
Thiazine dyes, 102 
Thiocyanates, 67 
Thioglycollic acid, Dissociation 
constant of, 151 
Tin and hydrochloric acid as re- 
ducing agent, 92 
Tollen’s reagent, 32 
Preparation of, 32 
Toluene, Action of concentrated 
sulphuric acid on, 88 
as a solvent for anthracene, 
127 
o-Toluidine hydrochloride, De- 
gree of hydrolysis of, 155 
p-Toluidine in the preparation of 
mauve, 103 
hydrochloride, Degree of hy- 
drolysis of, 155 
use of, in making parafuchsine, 
120 
Toluylene blue, 102 
2,4,6-Tribromphenol, 104 
Trichloracetic acid, Dissociation 
constant of, 151 


INDEX 


Trichlorlactic acid, Dissociation 
constant of, 151 
Triethylammonium bromide, 50 
hydroxide, Dissociation con- 
stant of, 154 
Triethylamine, 51 
Trimethylammonium hydroxide, 
Dissociation constant of, 
154 
Trimethylsulphonium iodide, 44 
Triphenylmethane, Derivatives 
of, 119 
Tubes, Dissolving-, 162 
Dropping-, 22 
Ebullition-, 6 
Twaddell’s hydrometer, 144 
Readings of, 144 


Ultramicroscope with colloids, 


Units, Heat, 140 
Urea, Wéhler’s synthesis of, 69 
Action of alkaline hypobro- 
mite on, 69 
Action of nitric acid on, 69 
Action of sodium hydroxide 
on, 69 
Dissociation constant of, 154 
hydrochloride, Degree of hy- 
drolysis of, 155 
quantitative estimation of, 69 
synthesis of, from phosgene, 69 
Uric acid, Conversion into mur- 
exid, 70 


Vacuum desiccator, Use of, 31 

Valerianic acid, Dissociation con- 
stant of, 151 

von Baeyer’s test for the ‘‘ double 
bond,” 12 

Villiger, 34 


Walden, 154 

Walker, 154 

Water, Dissociation constant of, 
150 


INDEX 191 


Water, Action of calcium carbide Zinc dust as a reducing agent, 


on, 13 
Test for, in alcohol, 8 chloride anhydrous as a con- 
Wohler’s synthesis of urea, 69 densing agent, 119 


copper couple, 134 
1-Xylose, Action of Fehling’s so- ° ethyl, preparation of, 134 
lution on, 75 Reactions of, 134, 135 


Gn a, 

















